Difference between one-to-many and many-to-one relationship

One-to-many and Many-to-one relationship is talking about the same logical relationship, eg an Owner may have many Homes, but a Home can only have one Owner.

So in this example Owner is the One, and Homes are the Many. Each Home always has an owner_id (eg the Foreign Key) as an extra column.

The difference in implementation between these two, is which table defines the relationship. In One-to-Many, the Owner is where the relationship is defined. Eg, owner1.homes lists all the homes with owner1's owner_id In Many-to-One, the Home is where the relationship is defined. Eg, home1.owner lists owner1's owner_id.

I dont actually know in what instance you would implement the many-to-one arrangement, because it seems a bit redundant as you already know the owner_id. Perhaps its related to cleanness of deletions and changes.

How can I use querySelector on to pick an input element by name?

1- you need to close the block of the function with '}', which is missing.

2- the argument of querySelector may not be an empty string '' or ' '... Use '*' for all.

3- those arguments will return the needed value:

querySelector('*')

querySelector('input')

querySelector('input[name="pwd"]')

querySelector('[name="pwd"]')

What does "request for member '*******' in something not a structure or union" mean?

I saw this when I was trying to access the members.

My struct was this:

struct test { 
    int a;
    int b;
};
    
struct test testvar;

Normally we access structure members as

testvar.a;
testvar.b;

I mistook testvar to be a pointer and did this.

testvar->a;

That's when I saw this error.

request for member ‘a’ in something not a structure or union

Linq filter List<string> where it contains a string value from another List<string>

Try the following:

var filteredFileSet = fileList.Where(item => filterList.Contains(item));

When you iterate over filteredFileSet (See LINQ Execution) it will consist of a set of IEnumberable values. This is based on the Where Operator checking to ensure that items within the fileList data set are contained within the filterList set.

As fileList is an IEnumerable set of string values, you can pass the 'item' value directly into the Contains method.

Include another HTML file in a HTML file

I have one more solution to do this

Using Ajax in javascript

here is the explained code in Github repo https://github.com/dupinder/staticHTML-Include

basic idea is:

index.html

<!DOCTYPE html>
<html>
<head>
    <meta charset='utf-8'>
    <meta http-equiv='X-UA-Compatible' content='IE=edge'>
    <title>Page Title</title>
    <meta name='viewport' content='width=device-width, initial-scale=1'>
    <script src='main.js'></script>


</head>
<body>
    <header></header>

    <footer></footer>
</body>
</html>

main.js

fetch("./header.html")
  .then(response => {
    return response.text()
  })
  .then(data => {
    document.querySelector("header").innerHTML = data;
  });

fetch("./footer.html")
  .then(response => {
    return response.text()
  })
  .then(data => {
    document.querySelector("footer").innerHTML = data;
  });

How to check the version of GitLab?

If you are using a self-hosted version of GitLab then you may consider running this command.

grep gitlab /opt/gitlab/version-manifest.txt

Creating a config file in PHP

One simple but elegant way is to create a config.php file (or whatever you call it) that just returns an array:

<?php

return array(
    'host' => 'localhost',
    'username' => 'root',
);

And then:

$configs = include('config.php');

Add data dynamically to an Array

$dynamicarray = array();

for($i=0;$i<10;$i++)
{
    $dynamicarray[$i]=$i;
}

How to display errors on laravel 4?

Maybe not on Laravel 4 this time, but on L5.2* I had similar issue:

I simply changed the ownership of the storage/logs directory to www-data with:

# chown -R www-data:www-data logs

PS: This is on Ubuntu 15 and with apache.

My logs directory now looks like:

drwxrwxr-x  2 www-data   www-data 4096 jaan  23 09:39 logs/

Python/Django: log to console under runserver, log to file under Apache

This works quite well in my local.py, saves me messing up the regular logging:

from .settings import *

LOGGING['handlers']['console'] = {
    'level': 'DEBUG',
    'class': 'logging.StreamHandler',
    'formatter': 'verbose'
}
LOGGING['loggers']['foo.bar'] = {
    'handlers': ['console'],
    'propagate': False,
    'level': 'DEBUG',
}

Android: How can I pass parameters to AsyncTask's onPreExecute()?

1) For me that's the most simple way passing parameters to async task is like this

// To call the async task do it like this
Boolean[] myTaskParams = { true, true, true };
myAsyncTask = new myAsyncTask ().execute(myTaskParams);

Declare and use the async task like here

private class myAsyncTask extends AsyncTask<Boolean, Void, Void> {

    @Override
    protected Void doInBackground(Boolean...pParams) 
    {
        Boolean param1, param2, param3;

        //

          param1=pParams[0];    
          param2=pParams[1];
          param3=pParams[2];    
      ....
}

2) Passing methods to async-task In order to avoid coding the async-Task infrastructure (thread, messagenhandler, ...) multiple times you might consider to pass the methods which should be executed in your async-task as a parameter. Following example outlines this approach. In addition you might have the need to subclass the async-task to pass initialization parameters in the constructor.

 /* Generic Async Task    */
interface MyGenericMethod {
    int execute(String param);
}

protected class testtask extends AsyncTask<MyGenericMethod, Void, Void>
{
    public String mParam;                           // member variable to parameterize the function
    @Override
    protected Void doInBackground(MyGenericMethod... params) {
        //  do something here
        params[0].execute("Myparameter");
        return null;
    }       
}

// to start the asynctask do something like that
public void startAsyncTask()
{
    // 
    AsyncTask<MyGenericMethod, Void, Void>  mytest = new testtask().execute(new MyGenericMethod() {
        public int execute(String param) {
            //body
            return 1;
        }
    });     
}

Add a common Legend for combined ggplots

@Guiseppe:

I have no idea of Grobs etc whatsoever, but I hacked together a solution for two plots, should be possible to extend to arbitrary number but its not in a sexy function:

plots <- list(p1, p2)
g <- ggplotGrob(plots[[1]] + theme(legend.position="bottom"))$grobs
legend <- g[[which(sapply(g, function(x) x$name) == "guide-box")]]
lheight <- sum(legend$height)
tmp <- arrangeGrob(p1 + theme(legend.position = "none"), p2 + theme(legend.position = "none"), layout_matrix = matrix(c(1, 2), nrow = 1))
grid.arrange(tmp, legend, ncol = 1, heights = unit.c(unit(1, "npc") - lheight, lheight))

How to initialize a private static const map in C++?

I did it! :)

Works fine without C++11

class MyClass {
    typedef std::map<std::string, int> MyMap;

    struct T {
        const char* Name;
        int Num;

        operator MyMap::value_type() const {
            return std::pair<std::string, int>(Name, Num);
        }
    };

    static const T MapPairs[];
    static const MyMap TheMap;
};

const MyClass::T MyClass::MapPairs[] = {
    { "Jan", 1 }, { "Feb", 2 }, { "Mar", 3 }
};

const MyClass::MyMap MyClass::TheMap(MapPairs, MapPairs + 3);

C# How to determine if a number is a multiple of another?

I don't get that part about the string stuff, but why don't you use the modulo operator (%) to check if a number is dividable by another? If a number is dividable by another, the other is automatically a multiple of that number.

It goes like that:

   int a = 10; int b = 5;

   // is a a multiple of b 
   if ( a % b == 0 )  ....

Simple WPF RadioButton Binding?

I came up with a simple solution.

I have a model.cs class with:

private int _isSuccess;
public int IsSuccess { get { return _isSuccess; } set { _isSuccess = value; } }

I have Window1.xaml.cs file with DataContext set to model.cs. The xaml contains the radiobuttons:

<RadioButton IsChecked="{Binding Path=IsSuccess, Converter={StaticResource radioBoolToIntConverter}, ConverterParameter=1}" Content="one" />
<RadioButton IsChecked="{Binding Path=IsSuccess, Converter={StaticResource radioBoolToIntConverter}, ConverterParameter=2}" Content="two" />
<RadioButton IsChecked="{Binding Path=IsSuccess, Converter={StaticResource radioBoolToIntConverter}, ConverterParameter=3}" Content="three" />

Here is my converter:

public class RadioBoolToIntConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        int integer = (int)value;
        if (integer==int.Parse(parameter.ToString()))
            return true;
        else
            return false;
    }

    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        return parameter;
    }
}

And of course, in Window1's resources:

<Window.Resources>
    <local:RadioBoolToIntConverter x:Key="radioBoolToIntConverter" />
</Window.Resources>

How to implement authenticated routes in React Router 4?

My Previous answer is not scalable. Here is what I think is good approach-

Your Routes-

<Switch>
  <Route
    exact path="/"
    component={matchStateToProps(InitialAppState, {
      routeOpen: true // no auth is needed to access this route
    })} />
  <Route
    exact path="/profile"
    component={matchStateToProps(Profile, {
      routeOpen: false // can set it false or just omit this key
    })} />
  <Route
    exact path="/login"
    component={matchStateToProps(Login, {
      routeOpen: true
    })} />
  <Route
    exact path="/forgot-password"
    component={matchStateToProps(ForgotPassword, {
      routeOpen: true
    })} />
  <Route
    exact path="/dashboard"
    component={matchStateToProps(DashBoard)} />
</Switch>

Idea is to use a wrapper in component props which would return original component if no auth is required or already authenticated otherwise would return default component e.g. Login.

const matchStateToProps = function(Component, defaultProps) {
  return (props) => {
    let authRequired = true;

    if (defaultProps && defaultProps.routeOpen) {
      authRequired = false;
    }

    if (authRequired) {
      // check if loginState key exists in localStorage (Your auth logic goes here)
      if (window.localStorage.getItem(STORAGE_KEYS.LOGIN_STATE)) {
        return <Component { ...defaultProps } />; // authenticated, good to go
      } else {
        return <InitialAppState { ...defaultProps } />; // not authenticated
      }
    }
    return <Component { ...defaultProps } />; // no auth is required
  };
};

Download file of any type in Asp.Net MVC using FileResult?

its simple just give your physical path in directoryPath with file name

public FilePathResult GetFileFromDisk(string fileName)
{
    return File(directoryPath, "multipart/form-data", fileName);
}

Disabling Controls in Bootstrap

Try

<select id="xxx" name="xxx" class="input-medium" disabled>

How to use XPath in Python?

If you want to have the power of XPATH combined with the ability to also use CSS at any point you can use parsel:

>>> from parsel import Selector
>>> sel = Selector(text=u"""<html>
        <body>
            <h1>Hello, Parsel!</h1>
            <ul>
                <li><a href="http://example.com">Link 1</a></li>
                <li><a href="http://scrapy.org">Link 2</a></li>
            </ul
        </body>
        </html>""")
>>>
>>> sel.css('h1::text').extract_first()
'Hello, Parsel!'
>>> sel.xpath('//h1/text()').extract_first()
'Hello, Parsel!'

What is the correct SQL type to store a .Net Timespan with values > 24:00:00?

I'd store it in the database as a BIGINT and I'd store the number of ticks (eg. TimeSpan.Ticks property).

That way, if I wanted to get a TimeSpan object when I retrieve it, I could just do TimeSpan.FromTicks(value) which would be easy.

How do I make an asynchronous GET request in PHP?

For me the question about asynchronous GET request is appeared because of I met with situation when I need to do hundreds of requests, get and deal with result data on every request and every request takes significant milliseconds of executing that leads to minutes(!) of total executing with simple file_get_contents.

In this case it was very helpful comment of w_haigh at php.net on function http://php.net/manual/en/function.curl-multi-init.php

So, here is my upgraded and cleaned version of making lot of requests simultaneously. For my case it's equivalent to "asynchronous" way. May be it helps for someone!

// Build the multi-curl handle, adding both $ch
$mh = curl_multi_init();

// Build the individual requests, but do not execute them
$chs = [];
$chs['ID0001'] = curl_init('http://webservice.example.com/?method=say&word=Hello');
$chs['ID0002'] = curl_init('http://webservice.example.com/?method=say&word=World');
// $chs[] = ...
foreach ($chs as $ch) {
    curl_setopt_array($ch, [
        CURLOPT_RETURNTRANSFER => true,  // Return requested content as string
        CURLOPT_HEADER => false,         // Don't save returned headers to result
        CURLOPT_CONNECTTIMEOUT => 10,    // Max seconds wait for connect
        CURLOPT_TIMEOUT => 20,           // Max seconds on all of request
        CURLOPT_USERAGENT => 'Robot YetAnotherRobo 1.0',
    ]);

    // Well, with a little more of code you can use POST queries too
    // Also, useful options above can be  CURLOPT_SSL_VERIFYHOST => 0  
    // and  CURLOPT_SSL_VERIFYPEER => false ...

    // Add every $ch to the multi-curl handle
    curl_multi_add_handle($mh, $ch);
}

// Execute all of queries simultaneously, and continue when ALL OF THEM are complete
$running = null;
do {
    curl_multi_exec($mh, $running);
} while ($running);

// Close the handles
foreach ($chs as $ch) {
    curl_multi_remove_handle($mh, $ch);
}
curl_multi_close($mh);

// All of our requests are done, we can now access the results
// With a help of ids we can understand what response was given
// on every concrete our request
$responses = [];
foreach ($chs as $id => $ch) {
    $responses[$id] = curl_multi_getcontent($ch);
    curl_close($ch);
}
unset($chs); // Finita, no more need any curls :-)

print_r($responses); // output results

It's easy to rewrite this to handle POST or other types of HTTP(S) requests or any combinations of them. And Cookie support, redirects, http-auth, etc.

How to use parameters with HttpPost

Generally speaking an HTTP POST assumes the content of the body contains a series of key/value pairs that are created (most usually) by a form on the HTML side. You don't set the values using setHeader, as that won't place them in the content body.

So with your second test, the problem that you have here is that your client is not creating multiple key/value pairs, it only created one and that got mapped by default to the first argument in your method.

There are a couple of options you can use. First, you could change your method to accept only one input parameter, and then pass in a JSON string as you do in your second test. Once inside the method, you then parse the JSON string into an object that would allow access to the fields.

Another option is to define a class that represents the fields of the input types and make that the only input parameter. For example

class MyInput
{
    String str1;
    String str2;

    public MyInput() { }
      //  getters, setters
 }

@POST
@Consumes({"application/json"})
@Path("create/")
public void create(MyInput in){
System.out.println("value 1 = " + in.getStr1());
System.out.println("value 2 = " + in.getStr2());
}

Depending on the REST framework you are using it should handle the de-serialization of the JSON for you.

The last option is to construct a POST body that looks like:

str1=value1&str2=value2

then add some additional annotations to your server method:

public void create(@QueryParam("str1") String str1, 
                  @QueryParam("str2") String str2)

@QueryParam doesn't care if the field is in a form post or in the URL (like a GET query).

If you want to continue using individual arguments on the input then the key is generate the client request to provide named query parameters, either in the URL (for a GET) or in the body of the POST.

How to view the list of compile errors in IntelliJ?

A more up to date answer for anyone else who comes across this:

(from https://www.jetbrains.com/help/idea/eclipse.html, §Auto-compilation; click for screenshots)

Compile automatically:

To enable automatic compilation, navigate to Settings/Preferences | Build, Execution, Deployment | Compiler and select the Build project automatically option

Show all errors in one place:

The Problems tool window appears if the Make project automatically option is enabled in the Compiler settings. It shows a list of problems that were detected on project compilation.

Use the Eclipse compiler: This is actually bundled in IntelliJ. It gives much more useful error messages, in my opinion, and, according to this blog, it's much faster since it was designed to run in the background of an IDE and uses incremental compilation.

While Eclipse uses its own compiler, IntelliJ IDEA uses the javac compiler bundled with the project JDK. If you must use the Eclipse compiler, navigate to Settings/Preferences | Build, Execution, Deployment | Compiler | Java Compiler and select it... The biggest difference between the Eclipse and javac compilers is that the Eclipse compiler is more tolerant to errors, and sometimes lets you run code that doesn't compile.

How to get element value in jQuery

Use .text() or .html()

$("#list li").click(function() {
        var selected = $(this).text();
        alert(selected);
});

How to set IntelliJ IDEA Project SDK

For IntelliJ IDEA 2017.2 I did the following to fix this issue: Go to your project structure Now go to SDKs under platform settings and click the green add button. Add your JDK path. In my case it was this path C:\Program Files\Java\jdk1.8.0_144 Now Just go Project under Project settings and select the project SDK.

Moving uncommitted changes to a new branch

Just create a new branch with git checkout -b ABC_1; your uncommitted changes will be kept, and you then commit them to that branch.

When should I use Lazy<T>?

From MSDN:

Use an instance of Lazy to defer the creation of a large or resource-intensive object or the execution of a resource-intensive task, particularly when such creation or execution might not occur during the lifetime of the program.

In addition to James Michael Hare's answer, Lazy provides thread-safe initialization of your value. Take a look at LazyThreadSafetyMode enumeration MSDN entry describing various types of thread safety modes for this class.

How do I use a regex in a shell script?

the problem is you're trying to use regex features not supported by grep. namely, your \d won't work. use this instead:

REGEX_DATE="^[[:digit:]]{2}[-/][[:digit:]]{2}[-/][[:digit:]]{4}$"
echo "$1" | grep -qE "${REGEX_DATE}"
echo $?

you need the -E flag to get ERE in order to use {#} style.

How can I convert String to Int?

Convert.ToInt32( TextBoxD1.Text );

Use this if you feel confident that the contents of the text box is a valid int. A safer option is

int val = 0;
Int32.TryParse( TextBoxD1.Text, out val );

This will provide you with some default value you can use. Int32.TryParse also returns a Boolean value indicating whether it was able to parse or not, so you can even use it as the condition of an if statement.

if( Int32.TryParse( TextBoxD1.Text, out val ){
  DoSomething(..);
} else {
  HandleBadInput(..);
}

How to listen state changes in react.js?

Using useState with useEffect as described above is absolutely correct way. But if getSearchResults function returns subscription then useEffect should return a function which will be responsible for unsubscribing the subscription . Returned function from useEffect will run before each change to dependency(name in above case) and on component destroy

Is it possible to set transparency in CSS3 box-shadow?

I suppose rgba() would work here. After all, browser support for both box-shadow and rgba() is roughly the same.

/* 50% black box shadow */
box-shadow: 10px 10px 10px rgba(0, 0, 0, 0.5);

_x000D_

div {_x000D_
    width: 200px;_x000D_
    height: 50px;_x000D_
    line-height: 50px;_x000D_
    text-align: center;_x000D_
    color: white;_x000D_
    background-color: red;_x000D_
    margin: 10px;_x000D_
}_x000D_
_x000D_
div.a {_x000D_
  box-shadow: 10px 10px 10px #000;_x000D_
}_x000D_
_x000D_
div.b {_x000D_
  box-shadow: 10px 10px 10px rgba(0, 0, 0, 0.5);_x000D_
}

_x000D_

<div class="a">100% black shadow</div>_x000D_
<div class="b">50% black shadow</div>

_x000D_

How do I link a JavaScript file to a HTML file?

this is demo code but it will help 

<!DOCTYPE html>
<html>
<head>
<title>APITABLE 3</title>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.4.1/jquery.min.js"></script>
<script>


$(document).ready(function(){

$.ajax({
    type: "GET",
    url: "https://reqres.in/api/users/",

    data: '$format=json',

    dataType: 'json',
    success: function (data) {
 $.each(data.data,function(d,results){
     console.log(data);

 $("#apiData").append(
                        "<tr>"
                          +"<td>"+results.first_name+"</td>"
                          +"<td>"+results.last_name+"</td>"
                          +"<td>"+results.id+"</td>"
                          +"<td>"+results.email+"</td>"
  +"<td>"+results.bentrust+"</td>"
                        +"</tr>" )
                    })
 } 

});

});


</script>
</head>
<body>


    <table id="apiTable">

        <thead>
            <tr>
            <th>Id</th>
            <br>
            <th>Email</th>
            <br>
            <th>Firstname</th>
            <br>
            <th>Lastname</th>
        </tr>
        </thead>
        <tbody id="apiData"></tbody>    





</body>
</html>

Curl to return http status code along with the response

I was able to get a solution by looking at the curl doc which specifies to use - for the output to get the output to stdout.

curl -o - http://localhost

To get the response with just the http return code, I could just do

curl -o /dev/null -s -w "%{http_code}\n" http://localhost

Add User to Role ASP.NET Identity

Below is an alternative implementation of a 'create user' controller method using Claims based roles.

The created claims then work with the Authorize attribute e.g. [Authorize(Roles = "Admin, User.*, User.Create")]

    // POST api/User/Create
    [Route("Create")]
    public async Task<IHttpActionResult> Create([FromBody]CreateUserModel model)
    {
        if (!ModelState.IsValid)
        {
            return BadRequest(ModelState);
        }

        // Generate long password for the user
        var password = System.Web.Security.Membership.GeneratePassword(25, 5);

        // Create the user
        var user = new ApiUser() { UserName = model.UserName };
        var result = await UserManager.CreateAsync(user, password);
        if (!result.Succeeded)
        {
            return GetErrorResult(result);
        }

        // Add roles (permissions) for the user
        foreach (var perm in model.Permissions)
        {
            await UserManager.AddClaimAsync(user.Id, new Claim(ClaimTypes.Role, perm));
        }

        return Ok<object>(new { UserName = user.UserName, Password = password });
    }

versionCode vs versionName in Android Manifest

android:versionCode — An integer value that represents the version of the application code, relative to other versions.

The value is an integer so that other applications can programmatically evaluate it, for example to check an upgrade or downgrade relationship. You can set the value to any integer you want, however you should make sure that each successive release of your application uses a greater value. The system does not enforce this behavior, but increasing the value with successive releases is normative.

android:versionName — A string value that represents the release version of the application code, as it should be shown to users.

The value is a string so that you can describe the application version as a .. string, or as any other type of absolute or relative version identifier.

As with android:versionCode, the system does not use this value for any internal purpose, other than to enable applications to display it to users. Publishing services may also extract the android:versionName value for display to users.

Typically, you would release the first version of your application with versionCode set to 1, then monotonically increase the value with each release, regardless whether the release constitutes a major or minor release. This means that the android:versionCode value does not necessarily have a strong resemblance to the application release version that is visible to the user (see android:versionName, below). Applications and publishing services should not display this version value to users.

Finding out the name of the original repository you cloned from in Git

In the repository root, the .git/config file holds all information about remote repositories and branches. In your example, you should look for something like:

[remote "origin"]
    fetch = +refs/heads/*:refs/remotes/origin/*
    url = server:gitRepo.git

Also, the Git command git remote -v shows the remote repository name and URL. The "origin" remote repository usually corresponds to the original repository, from which the local copy was cloned.

Name attribute in @Entity and @Table

@Entity(name = "someThing") => this name will be used to name the Entity
@Table(name = "someThing")  => this name will be used to name a table in DB

So, in the first case your table and entity will have the same name, that will allow you to access your table with the same name as the entity while writing HQL or JPQL.

And in second case while writing queries you have to use the name given in @Entity and the name given in @Table will be used to name the table in the DB.

So in HQL your someThing will refer to otherThing in the DB.

Get value from SimpleXMLElement Object

try current($xml->code[0]->lat)

it returns element under current pointer of array, which is 0, so you will get value

How to detect when keyboard is shown and hidden

So ah, this is the real answer now.

import Combine


class MrEnvironmentObject {
    /// Bind into yr SwiftUI views
    @Published public var isKeyboardShowing: Bool = false

    /// Keep 'em from deallocatin'
    var subscribers: [AnyCancellable]? = nil

    /// Adds certain Combine subscribers that will handle updating the
    ///  `isKeyboardShowing` property 
    ///
    /// - Parameter host: the UIHostingController of your views. 
    func setupSubscribers<V: View>(
        host: inout UIHostingController<V>
    ) {
        subscribers = [
            NotificationCenter
                .default
                .publisher(for: UIResponder.keyboardWillShowNotification)
                .sink { [weak self] _ in
                    self?.isKeyboardShowing = true
                },
            NotificationCenter
                .default
                .publisher(for: UIResponder.keyboardWillHideNotification)
                .sink { [weak self, weak host] _ in
                    self?.isKeyboardShowing = false
                    // Hidden gem, ask me how I know:
                    UIAccessibility.post(
                        notification: .layoutChanged, 
                        argument: host
                    )
                },
            // ...
            Profit
                .sink { [weak self] profit in profit() },
        ]
    }
}

callback to handle completion of pipe

Based nodejs document, http://nodejs.org/api/stream.html#stream_event_finish, it should handle writableStream's finish event.

var writable = getWriteable();
var readable = getReadable();
readable.pipe(writable);
writable.on('finish', function(){ ... });

How many socket connections can a web server handle?

This question is a fairly difficult one. There is no real software limitation on the number of active connections a machine can have, though some OS's are more limited than others. The problem becomes one of resources. For example, let's say a single machine wants to support 64,000 simultaneous connections. If the server uses 1MB of RAM per connection, it would need 64GB of RAM. If each client needs to read a file, the disk or storage array access load becomes much larger than those devices can handle. If a server needs to fork one process per connection then the OS will spend the majority of its time context switching or starving processes for CPU time.

The C10K problem page has a very good discussion of this issue.

How to determine the current iPhone/device model?

Swift 3.0 or higher

import UIKit

class ViewController: UIViewController {

    let device = UIDevice.current

    override func viewDidLoad() {
        super.viewDidLoad()

        let model = device.model
        print(model) // e.g. "iPhone"

        let modelName = device.modelName
        print(modelName) // e.g. "iPhone 6"  /* see the extension */

        let deviceName = device.name
        print(deviceName) // e.g. "My iPhone"

        let systemName = device.systemName
        print(systemName) // e.g. "iOS"

        let systemVersion = device.systemVersion
        print(systemVersion) // e.g. "10.3.2"

        if let identifierForVendor = device.identifierForVendor {

            print(identifierForVendor) // e.g. "E1X2XX34-5X6X-7890-123X-XXX456C78901"
        }
    }
}

and add the following extension

extension UIDevice {

    var modelName: String {

        var systemInfo = utsname()
        uname(&systemInfo)

        let machineMirror = Mirror(reflecting: systemInfo.machine)

        let identifier = machineMirror.children.reduce("") { identifier, element in
            guard let value = element.value as? Int8, value != 0 else { return identifier }
            return identifier + String(UnicodeScalar(UInt8(value)))
        }

        switch identifier {

        case "iPod5,1":                                 return "iPod Touch 5"
        case "iPod7,1":                                 return "iPod Touch 6"
        case "iPhone3,1", "iPhone3,2", "iPhone3,3":     return "iPhone 4"
        case "iPhone4,1":                               return "iPhone 4s"
        case "iPhone5,1", "iPhone5,2":                  return "iPhone 5"
        case "iPhone5,3", "iPhone5,4":                  return "iPhone 5c"
        case "iPhone6,1", "iPhone6,2":                  return "iPhone 5s"
        case "iPhone7,2":                               return "iPhone 6"
        case "iPhone7,1":                               return "iPhone 6 Plus"
        case "iPhone8,1":                               return "iPhone 6s"
        case "iPhone8,2":                               return "iPhone 6s Plus"
        case "iPhone9,1", "iPhone9,3":                  return "iPhone 7"
        case "iPhone9,2", "iPhone9,4":                  return "iPhone 7 Plus"
        case "iPhone8,4":                               return "iPhone SE"
        case "iPad2,1", "iPad2,2", "iPad2,3", "iPad2,4":return "iPad 2"
        case "iPad3,1", "iPad3,2", "iPad3,3":           return "iPad 3"
        case "iPad3,4", "iPad3,5", "iPad3,6":           return "iPad 4"
        case "iPad4,1", "iPad4,2", "iPad4,3":           return "iPad Air"
        case "iPad5,3", "iPad5,4":                      return "iPad Air 2"
        case "iPad6,11", "iPad6,12":                    return "iPad 5"
        case "iPad2,5", "iPad2,6", "iPad2,7":           return "iPad Mini"
        case "iPad4,4", "iPad4,5", "iPad4,6":           return "iPad Mini 2"
        case "iPad4,7", "iPad4,8", "iPad4,9":           return "iPad Mini 3"
        case "iPad5,1", "iPad5,2":                      return "iPad Mini 4"
        case "iPad6,3", "iPad6,4":                      return "iPad Pro 9.7 Inch"
        case "iPad6,7", "iPad6,8":                      return "iPad Pro 12.9 Inch"
        case "iPad7,1", "iPad7,2":                      return "iPad Pro 12.9 Inch 2. Generation"
        case "iPad7,3", "iPad7,4":                      return "iPad Pro 10.5 Inch"
        case "AppleTV5,3":                              return "Apple TV"
        case "i386", "x86_64":                          return "Simulator"
        default:                                        return identifier
        }
    }
}

Launch iOS simulator from Xcode and getting a black screen, followed by Xcode hanging and unable to stop tasks

This could result from not setting the correct deployment info. (i.e. if your storyboard isn't set as the main interface)

How can I include null values in a MIN or MAX?

I try to use a union to combine two queries to format the returns you want:

SELECT recordid, startdate, enddate FROM tmp Where enddate is null UNION SELECT recordid, MIN(startdate), MAX(enddate) FROM tmp GROUP BY recordid

But I have no idea if the Union would have great impact on the performance

Angular 2: How to call a function after get a response from subscribe http.post

You can code as a lambda expression as the third parameter(on complete) to the subscribe method. Here I re-set the departmentModel variable to the default values.

saveData(data:DepartmentModel){
  return this.ds.sendDepartmentOnSubmit(data).
  subscribe(response=>this.status=response,
   ()=>{},
   ()=>this.departmentModel={DepartmentId:0});
}

How to put a div in center of browser using CSS?

.center {
  margin: auto;
  margin-top: 15vh;
}

Should do the trick

'python3' is not recognized as an internal or external command, operable program or batch file

Python3.exe is not defined in windows

Specify the path for required version of python when you need to used it by creating virtual environment for your project

Python 3

virtualenv --python=C:\PATH_TO_PYTHON\python.exe environment

Python2

virtualenv --python=C:\PATH_TO_PYTHON\python.exe environment

then activate the environment using

.\environment\Scripts\activate.ps1

How can I get table names from an MS Access Database?

Schema information which is designed to be very close to that of the SQL-92 INFORMATION_SCHEMA may be obtained for the Jet/ACE engine (which is what I assume you mean by 'access') via the OLE DB providers.

See:

OpenSchema Method (ADO)

Supported Schema Rowsets

Why does JSHint throw a warning if I am using const?

Creating a .jshintrc file is not necessary.

If you are using ECMAScript 6 then all you need to do is tell JSHint that:

Go to File > Settings
Navigate to Languages & Frameworks > JavaScript > Code Quality Tools > JSHint.
Scroll down to find Warn about incompatibilities with the specified ECMAScript version.
Click on Set.
Enter 6 and then press [Set].
Click [OK]

How to initialize/instantiate a custom UIView class with a XIB file in Swift

override func draw(_ rect: CGRect) 
{
    AlertView.layer.cornerRadius = 4
    AlertView.clipsToBounds = true

    btnOk.layer.cornerRadius = 4
    btnOk.clipsToBounds = true   
}

class func instanceFromNib() -> LAAlertView {
    return UINib(nibName: "LAAlertView", bundle: nil).instantiate(withOwner: nil, options: nil)[0] as! LAAlertView
}

@IBAction func okBtnDidClicked(_ sender: Any) {

    removeAlertViewFromWindow()

    UIView.animate(withDuration: 0.4, delay: 0.0, options: .allowAnimatedContent, animations: {() -> Void in
        self.AlertView.transform = CGAffineTransform(scaleX: 0.1, y: 0.1)

    }, completion: {(finished: Bool) -> Void in
        self.AlertView.transform = CGAffineTransform.identity
        self.AlertView.transform = CGAffineTransform(scaleX: 0.0, y: 0.0)
        self.AlertView.isHidden = true
        self.AlertView.alpha = 0.0

        self.alpha = 0.5
    })
}


func removeAlertViewFromWindow()
{
    for subview  in (appDel.window?.subviews)! {
        if subview.tag == 500500{
            subview.removeFromSuperview()
        }
    }
}


public func openAlertView(title:String , string : String ){

    lblTital.text  = title
    txtView.text  = string

    self.frame = CGRect(x: 0, y: 0, width: screenWidth, height: screenHeight)
    appDel.window!.addSubview(self)


    AlertView.alpha = 1.0
    AlertView.isHidden = false

    UIView.animate(withDuration: 0.2, animations: {() -> Void in
        self.alpha = 1.0
    })
    AlertView.transform = CGAffineTransform(scaleX: 0.0, y: 0.0)

    UIView.animate(withDuration: 0.3, delay: 0.2, options: .allowAnimatedContent, animations: {() -> Void in
        self.AlertView.transform = CGAffineTransform(scaleX: 1.1, y: 1.1)

    }, completion: {(finished: Bool) -> Void in
        UIView.animate(withDuration: 0.2, animations: {() -> Void in
            self.AlertView.transform = CGAffineTransform(scaleX: 1.0, y: 1.0)

        })
    })


}

SQL Server: Difference between PARTITION BY and GROUP BY

PARTITION BY is analytic, while GROUP BY is aggregate. In order to use PARTITION BY, you have to contain it with an OVER clause.

MVC Razor @foreach

When people say don't put logic in views, they're usually referring to business logic, not rendering logic. In my humble opinion, I think using @foreach in views is perfectly fine.

Add a new line to the end of a JtextArea

Are you using JTextArea's append(String) method to add additional text?

JTextArea txtArea = new JTextArea("Hello, World\n", 20, 20);
txtArea.append("Goodbye Cruel World\n");

asp.net mvc3 return raw html to view

What was working for me (ASP.NET Core), was to set return type ContentResult, then wrap the HMTL into it and set the ContentType to "text/html; charset=UTF-8". That is important, because, otherwise it will not be interpreted as HTML and the HTML language would be displayed as text.

Here's the example, part of a Controller class:

/// <summary>
/// Startup message displayed in browser.
/// </summary>
/// <returns>HTML result</returns>
[HttpGet]
public ContentResult Get()
{
    var result = Content("<html><title>DEMO</title><head><h2>Demo started successfully."
      + "<br/>Use <b><a href=\"http://localhost:5000/swagger\">Swagger</a></b>"
      + " to view API.</h2></head><body/></html>");
    result.ContentType = "text/html; charset=UTF-8";
    return result;
}

Regex to match URL end-of-line or "/" character

/(.+)/(\d{4}-\d{2}-\d{2})-(\d+)(/.*)?$

1st Capturing Group (.+)

.+ matches any character (except for line terminators)

+ Quantifier — Matches between one and unlimited times, as many times as possible, giving back as needed (greedy)

2nd Capturing Group (\d{4}-\d{2}-\d{2})

\d{4} matches a digit (equal to [0-9])

{4} Quantifier — Matches exactly 4 times

- matches the character - literally (case sensitive)

\d{2} matches a digit (equal to [0-9])

{2} Quantifier — Matches exactly 2 times

- matches the character - literally (case sensitive)

\d{2} matches a digit (equal to [0-9])

{2} Quantifier — Matches exactly 2 times

- matches the character - literally (case sensitive)

3rd Capturing Group (\d+)

\d+ matches a digit (equal to [0-9])

+ Quantifier — Matches between one and unlimited times, as many times as possible, giving back as needed (greedy)

4th Capturing Group (.*)?

? Quantifier — Matches between zero and one times, as many times as possible, giving back as needed (greedy)

.* matches any character (except for line terminators)

* Quantifier — Matches between zero and unlimited times, as many times as possible, giving back as needed (greedy)

$ asserts position at the end of the string

How to read data when some numbers contain commas as thousand separator?

If number is separated by "." and decimals by "," (1.200.000,00) in calling gsub you must set fixed=TRUE as.numeric(gsub(".","",y,fixed=TRUE))

What is the equivalent of Java's System.out.println() in Javascript?

In java System.out.println() prints something to console. In javascript same can be achieved using console.log().

You need to view browser console by pressing F12 key which opens developer tool and then switch to console tab.

Set a DateTime database field to "Now"

An alternative to GETDATE() is CURRENT_TIMESTAMP. Does the exact same thing.

Difference between two dates in MySQL

select 
unix_timestamp('2007-12-30 00:00:00') - 
unix_timestamp('2007-11-30 00:00:00');

Restart android machine

I think the only way to do this is to run another machine in parallel and use that machine to issue commands to your android box similar to how you would with a phone. If you have issues with the IP changing you can reserve an ip on your router and have the machine grab that one instead of asking the routers DHCP for one. This way you can ping the machine and figure out if it's done rebooting to continue the script.

click or change event on radio using jquery

This code worked for me:

$(function(){

    $('input:radio').change(function(){
        alert('changed');   
    });          

});

http://jsfiddle.net/3q29L/

Convert a string to a double - is this possible?

Why is floatval the best option for financial comparison data? bc functions only accurately turn strings into real numbers.

How can I rename a single column in a table at select?

If, like me, you are doing this for a column which then goes through COALESCE / array_to_json / ARRAY_AGG / row_to_json (PostgreSQL) and want to keep the capitals in the column name, double quote the column name, like so:

SELECT a.price AS "myFirstPrice", b.price AS "mySecondPrice"

Without the quotes (and when using those functions), my column names in camelCase would lose the capital letters.

VS Code - Search for text in all files in a directory

Enter Search Keyword in search (CTRL + SHIFT + F)
Exclude unwanted folder's/files by using exclude option (!)

ex: !Folder/File*
Hit Enter

Search results gives you desired result

JAXB: How to ignore namespace during unmarshalling XML document?

Another way to add a default namespace to an XML Document before feeding it to JAXB is to use JDom:

Parse XML to a Document
Iterate through and set namespace on all Elements
Unmarshall using a JDOMSource

Like this:

public class XMLObjectFactory {
    private static Namespace DEFAULT_NS = Namespace.getNamespace("http://tempuri.org/");

    public static Object createObject(InputStream in) {
        try {
            SAXBuilder sb = new SAXBuilder(false);
            Document doc = sb.build(in);
            setNamespace(doc.getRootElement(), DEFAULT_NS, true);
            Source src = new JDOMSource(doc);
            JAXBContext context = JAXBContext.newInstance("org.tempuri");
            Unmarshaller unmarshaller = context.createUnmarshaller();
            JAXBElement root = unmarshaller.unmarshal(src);
            return root.getValue();
        } catch (Exception e) {
            throw new RuntimeException("Failed to create Object", e);
        }
    }

    private static void setNamespace(Element elem, Namespace ns, boolean recurse) {
        elem.setNamespace(ns);
        if (recurse) {
            for (Object o : elem.getChildren()) {
                setNamespace((Element) o, ns, recurse);
            }
        }
    }

Handling ExecuteScalar() when no results are returned

In your case either the record doesn't exist with the userid=2 or it may contain a null value in first column, because if no value is found for the query result used in SQL command, ExecuteScalar() returns null.

Illegal string offset Warning PHP

TL;DR

You're trying to access a string as if it were an array, with a key that's a string. string will not understand that. In code we can see the problem:

"hello"["hello"];
// PHP Warning:  Illegal string offset 'hello' in php shell code on line 1

"hello"[0];
// No errors.

array("hello" => "val")["hello"];
// No errors. This is *probably* what you wanted.

In depth

Let's see that error:

Warning: Illegal string offset 'port' in ...

What does it say? It says we're trying to use the string 'port' as an offset for a string. Like this:

$a_string = "string";

// This is ok:
echo $a_string[0]; // s
echo $a_string[1]; // t
echo $a_string[2]; // r
// ...

// !! Not good:
echo $a_string['port'];
// !! Warning: Illegal string offset 'port' in ...

What causes this?

For some reason you expected an array, but you have a string. Just a mix-up. Maybe your variable was changed, maybe it never was an array, it's really not important.

What can be done?

If we know we should have an array, we should do some basic debugging to determine why we don't have an array. If we don't know if we'll have an array or string, things become a bit trickier.

What we can do is all sorts of checking to ensure we don't have notices, warnings or errors with things like is_array and isset or array_key_exists:

$a_string = "string";
$an_array = array('port' => 'the_port');

if (is_array($a_string) && isset($a_string['port'])) {
    // No problem, we'll never get here.
    echo $a_string['port'];
}

if (is_array($an_array) && isset($an_array['port'])) {
    // Ok!
    echo $an_array['port']; // the_port
}

if (is_array($an_array) && isset($an_array['unset_key'])) {
    // No problem again, we won't enter.
    echo $an_array['unset_key'];
}


// Similar, but with array_key_exists
if (is_array($an_array) && array_key_exists('port', $an_array)) {
    // Ok!
    echo $an_array['port']; // the_port
}

There are some subtle differences between isset and array_key_exists. For example, if the value of $array['key'] is null, isset returns false. array_key_exists will just check that, well, the key exists.

Intellij Cannot resolve symbol on import

IntelliJ has issues in resolving the dependencies. Try the following:

Right click on pom.xml -> Maven -> Reimport
Again Right click on pom.xml -> Maven -> Generate sources and update folders

How to read a Parquet file into Pandas DataFrame?

pandas 0.21 introduces new functions for Parquet:

pd.read_parquet('example_pa.parquet', engine='pyarrow')

pd.read_parquet('example_fp.parquet', engine='fastparquet')

The above link explains:

These engines are very similar and should read/write nearly identical parquet format files. These libraries differ by having different underlying dependencies (fastparquet by using numba, while pyarrow uses a c-library).

what is the differences between sql server authentication and windows authentication..?

If you wish to authenticate the users against windows system users [created by Administrator] then in that case you will go for Windows Authentication in your Application.

But in case you want to authenticate the users against set of users available in your application database, then in that case you will want to go for SQL Authentication.

Precisely if your application is an ASP.NET web-app, then you can use standard Login controls which depend on Providers like SqlMembershipProvider, SqlProfileProvider. You can configure your login controls and your application whether it should authenticate against windows users or app-database users. In the first case it will be called Windows Authentication and the later will be known as Sql Authentication.

How do you print in a Go test using the "testing" package?

The *_test.go file is a Go source like the others, you can initialize a new logger every time if you need to dump complex data structure, here an example:

// initZapLog is delegated to initialize a new 'log manager'
func initZapLog() *zap.Logger {
    config := zap.NewDevelopmentConfig()
    config.EncoderConfig.EncodeLevel = zapcore.CapitalColorLevelEncoder
    config.EncoderConfig.TimeKey = "timestamp"
    config.EncoderConfig.EncodeTime = zapcore.ISO8601TimeEncoder
    logger, _ := config.Build()
    return logger
}

Then, every time, in every test:

func TestCreateDB(t *testing.T) {
    loggerMgr := initZapLog()
    // Make logger avaible everywhere
    zap.ReplaceGlobals(loggerMgr)
    defer loggerMgr.Sync() // flushes buffer, if any
    logger := loggerMgr.Sugar()
    logger.Debug("START")
    conf := initConf()
    /* Your test here
    if false {
        t.Fail()
    }*/
}

Generating a Random Number between 1 and 10 Java

The standard way to do this is as follows:

Provide:

min Minimum value
max Maximum value

and get in return a Integer between min and max, inclusive.

Random rand = new Random();

// nextInt as provided by Random is exclusive of the top value so you need to add 1 

int randomNum = rand.nextInt((max - min) + 1) + min;

See the relevant JavaDoc.

As explained by Aurund, Random objects created within a short time of each other will tend to produce similar output, so it would be a good idea to keep the created Random object as a field, rather than in a method.

How to install a specific version of a package with pip?

Use ==:

pip install django_modeltranslation==0.4.0-beta2

Where does Hive store files in HDFS?

In Hive, tables are actually stored in a few places. Specifically, if you use partitions (which you should, if your tables are very large or growing) then each partition can have its own storage.

To show the default location where table data or partitions will be created if you create them through default HIVE commands: (insert overwrite ... partition ... and such):

describe formatted dbname.tablename

To show the actual location of a particular partition within a HIVE table, instead do this:

describe formatted dbname.tablename partition (name=value)

If you look in your filesystem where a table "should" live, and you find no files there, it's very likely that the table is created (usually incrementally) by creating a new partition and pointing that partition at some other location. This is a great way of building tables from things like daily imports from third parties and such, which avoids having to copy the files around or storing them more than once in different places.

How do I remove a MySQL database?

From the MySQL prompt:

mysql> drop database <db_name>;

Error:Conflict with dependency 'com.google.code.findbugs:jsr305'

When I added module: 'jsr305' as an additional exclude statement, it all worked out fine for me.

 androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
exclude group: 'com.android.support', module: 'support-annotations'
exclude module: 'jsr305'

})

Should I add the Visual Studio .suo and .user files to source control?

These files contain user preference configurations that are in general specific to your machine, so it's better not to put it in SCM. Also, VS will change it almost every time you execute it, so it will always be marked by the SCM as 'changed'. I don't include either, I'm in a project using VS for 2 years and had no problems doing that. The only minor annoyance is that the debug parameters (execution path, deployment target, etc.) are stored in one of those files (don't know which), so if you have a standard for them you won't be able to 'publish' it via SCM for other developers to have the entire development environment 'ready to use'.

Inserting the same value multiple times when formatting a string

>>> s1 ='arbit'
>>> s2 = 'hello world '.join( [s]*3 )
>>> print s2
arbit hello world arbit hello world arbit

How to check whether an array is empty using PHP?

Some decent answers, but just thought I'd expand a bit to explain more clearly when PHP determines if an array is empty.

Main Notes:

An array with a key (or keys) will be determined as NOT empty by PHP.

As array values need keys to exist, having values or not in an array doesn't determine if it's empty, only if there are no keys (AND therefore no values).

So checking an array with empty() doesn't simply tell you if you have values or not, it tells you if the array is empty, and keys are part of an array.

So consider how you are producing your array before deciding which checking method to use.
EG An array will have keys when a user submits your HTML form when each form field has an array name (ie name="array[]").
A non empty array will be produced for each field as there will be auto incremented key values for each form field's array.

Take these arrays for example:

/* Assigning some arrays */

// Array with user defined key and value
$ArrayOne = array("UserKeyA" => "UserValueA", "UserKeyB" => "UserValueB");

// Array with auto increment key and user defined value
// as a form field would return with user input
$ArrayTwo[] = "UserValue01";
$ArrayTwo[] = "UserValue02";

// Array with auto incremented key and no value
// as a form field would return without user input
$ArrayThree[] = '';
$ArrayThree[] = '';

If you echo out the array keys and values for the above arrays, you get the following:

ARRAY ONE:
[UserKeyA] => [UserValueA]
[UserKeyB] => [UserValueB]

ARRAY TWO:
[0] => [UserValue01]
[1] => [UserValue02]

ARRAY THREE:
[0] => []
[1] => []

And testing the above arrays with empty() returns the following results:

ARRAY ONE:
$ArrayOne is not empty

ARRAY TWO:
$ArrayTwo is not empty

ARRAY THREE:
$ArrayThree is not empty

An array will always be empty when you assign an array but don't use it thereafter, such as:

$ArrayFour = array();

This will be empty, ie PHP will return TRUE when using if empty() on the above.

So if your array has keys - either by eg a form's input names or if you assign them manually (ie create an array with database column names as the keys but no values/data from the database), then the array will NOT be empty().

In this case, you can loop the array in a foreach, testing if each key has a value. This is a good method if you need to run through the array anyway, perhaps checking the keys or sanitising data.

However it is not the best method if you simply need to know "if values exist" returns TRUE or FALSE. There are various methods to determine if an array has any values when it's know it will have keys. A function or class might be the best approach, but as always it depends on your environment and exact requirements, as well as other things such as what you currently do with the array (if anything).

Here's an approach which uses very little code to check if an array has values:

Using array_filter():
Iterates over each value in the array passing them to the callback function. If the callback function returns true, the current value from array is returned into the result array. Array keys are preserved.

$EmptyTestArray = array_filter($ArrayOne);

if (!empty($EmptyTestArray))
  {
    // do some tests on the values in $ArrayOne
  }
else
  {
    // Likely not to need an else, 
    // but could return message to user "you entered nothing" etc etc
  }

Running array_filter() on all three example arrays (created in the first code block in this answer) results in the following:

ARRAY ONE:
$arrayone is not empty

ARRAY TWO:
$arraytwo is not empty

ARRAY THREE:
$arraythree is empty

So when there are no values, whether there are keys or not, using array_filter() to create a new array and then check if the new array is empty shows if there were any values in the original array.
It is not ideal and a bit messy, but if you have a huge array and don't need to loop through it for any other reason, then this is the simplest in terms of code needed.

I'm not experienced in checking overheads, but it would be good to know the differences between using array_filter() and foreach checking if a value is found.

Obviously benchmark would need to be on various parameters, on small and large arrays and when there are values and not etc.

ALTER COLUMN in sqlite

While it is true that the is no ALTER COLUMN, if you only want to rename the column, drop the NOT NULL constraint, or change the data type, you can use the following set of dangerous commands:

PRAGMA writable_schema = 1;
UPDATE SQLITE_MASTER SET SQL = 'CREATE TABLE BOOKS ( title TEXT NOT NULL, publication_date TEXT)' WHERE NAME = 'BOOKS';
PRAGMA writable_schema = 0;

You will need to either close and reopen your connection or vacuum the database to reload the changes into the schema.

For example:

Y:\> **sqlite3 booktest**  
SQLite version 3.7.4  
Enter ".help" for instructions  
Enter SQL statements terminated with a ";"  
sqlite> **create table BOOKS ( title TEXT NOT NULL, publication_date TEXT NOT 
NULL);**  
sqlite> **insert into BOOKS VALUES ("NULLTEST",null);**  
Error: BOOKS.publication_date may not be NULL  
sqlite> **PRAGMA writable_schema = 1;**  
sqlite> **UPDATE SQLITE_MASTER SET SQL = 'CREATE TABLE BOOKS ( title TEXT NOT 
NULL, publication_date TEXT)' WHERE NAME = 'BOOKS';**  
sqlite> **PRAGMA writable_schema = 0;**  
sqlite> **.q**  

Y:\> **sqlite3 booktest**  
SQLite version 3.7.4  
Enter ".help" for instructions  
Enter SQL statements terminated with a ";"  
sqlite> **insert into BOOKS VALUES ("NULLTEST",null);**  
sqlite> **.q**

REFERENCES FOLLOW:

pragma writable_schema
When this pragma is on, the SQLITE_MASTER tables in which database can be changed using ordinary UPDATE, INSERT, and DELETE statements. Warning: misuse of this pragma can easily result in a corrupt database file.

[alter table](From http://www.sqlite.org/lang_altertable.html)
SQLite supports a limited subset of ALTER TABLE. The ALTER TABLE command in SQLite allows the user to rename a table or to add a new column to an existing table. It is not possible to rename a column, remove a column, or add or remove constraints from a table.

ALTER TABLE SYNTAX

Unknown Column In Where Clause

If you're trying to perform a query like the following (find all the nodes with at least one attachment) where you've used a SELECT statement to create a new field which doesn't actually exist in the database, and try to use the alias for that result you'll run into the same problem:

SELECT nodes.*, (SELECT (COUNT(*) FROM attachments 
WHERE attachments.nodeid = nodes.id) AS attachmentcount 
FROM nodes
WHERE attachmentcount > 0;

You'll get an error "Unknown column 'attachmentcount' in WHERE clause".

Solution is actually fairly simple - just replace the alias with the statement which produces the alias, eg:

SELECT nodes.*, (SELECT (COUNT(*) FROM attachments 
WHERE attachments.nodeid = nodes.id) AS attachmentcount 
FROM nodes 
WHERE (SELECT (COUNT(*) FROM attachments WHERE attachments.nodeid = nodes.id) > 0;

You'll still get the alias returned, but now SQL shouldn't bork at the unknown alias.

Method to Add new or update existing item in Dictionary

I know it is not Dictionary<TKey, TValue> class, however you can avoid KeyNotFoundException while incrementing a value like:

dictionary[key]++; // throws `KeyNotFoundException` if there is no such key

by using ConcurrentDictionary<TKey, TValue> and its really nice method AddOrUpdate()..

Let me show an example:

var str = "Hellooo!!!";
var characters = new ConcurrentDictionary<char, int>();
foreach (var ch in str)
    characters.AddOrUpdate(ch, 1, (k, v) => v + 1);

Remove Android App Title Bar

In your res/values/styles.xml of modern Android Studio projects (2019/2020) you should be able to change the default parent theme

<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">

I went one step further and had it look like this

<!-- Base application theme. -->
<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
    <!-- Customize your theme here. -->
    <item name="colorPrimary">@color/colorPrimary</item>
    <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
    <item name="colorAccent">@color/colorAccent</item>
    <item name="android:windowFullscreen">true</item>
</style>

This is based on the code generated from the Microsoft PWA builder https://www.pwabuilder.com/

IF EXISTS in T-SQL

There's no need for "else" in this case:

IF EXISTS(SELECT *  FROM  table1  WHERE Name='John' ) return 1
return 0

How to access a dictionary element in a Django template?

You need to find (or define) a 'get' template tag, for example, here.

The tag definition:

@register.filter
def hash(h, key):
    return h[key]

And it’s used like:

{% for o in objects %}
  <li>{{ dictionary|hash:o.id }}</li>
{% endfor %}

How do I return JSON without using a template in Django?

I think the issue has gotten confused regarding what you want. I imagine you're not actually trying to put the HTML in the JSON response, but rather want to alternatively return either HTML or JSON.

First, you need to understand the core difference between the two. HTML is a presentational format. It deals more with how to display data than the data itself. JSON is the opposite. It's pure data -- basically a JavaScript representation of some Python (in this case) dataset you have. It serves as merely an interchange layer, allowing you to move data from one area of your app (the view) to another area of your app (your JavaScript) which normally don't have access to each other.

With that in mind, you don't "render" JSON, and there's no templates involved. You merely convert whatever data is in play (most likely pretty much what you're passing as the context to your template) to JSON. Which can be done via either Django's JSON library (simplejson), if it's freeform data, or its serialization framework, if it's a queryset.

simplejson

from django.utils import simplejson

some_data_to_dump = {
   'some_var_1': 'foo',
   'some_var_2': 'bar',
}

data = simplejson.dumps(some_data_to_dump)

Serialization

from django.core import serializers

foos = Foo.objects.all()

data = serializers.serialize('json', foos)

Either way, you then pass that data into the response:

return HttpResponse(data, content_type='application/json')

[Edit] In Django 1.6 and earlier, the code to return response was

return HttpResponse(data, mimetype='application/json')

[EDIT]: simplejson was remove from django, you can use:

import json

json.dumps({"foo": "bar"})

Or you can use the django.core.serializers as described above.

Global constants file in Swift

Caseless enums can also be be used.

Advantage - They cannot be instantiated.

enum API {
    enum Endpoint {
        static let url1 = "url1"
        static let url2 = "url2"
    }
    enum BaseURL {
        static let dev = "dev"
        static let prod = "prod"
    }
}

Converting timestamp to time ago in PHP e.g 1 day ago, 2 days ago...

I found results like the following ugly:

1 years, 2 months, 0 days, 0 hours, 53 minutes and 1 seconds

Because of that I realized a function that respects plurals, removes empty values and optionally it is possible to shorten the output:

function since($timestamp, $level=6) {
    global $lang;
    $date = new DateTime();
    $date->setTimestamp($timestamp);
    $date = $date->diff(new DateTime());
    // build array
    $since = array_combine(array('year', 'month', 'day', 'hour', 'minute', 'second'), explode(',', $date->format('%y,%m,%d,%h,%i,%s')));
    // remove empty date values
    $since = array_filter($since);
    // output only the first x date values
    $since = array_slice($since, 0, $level);
    // build string
    $last_key = key(array_slice($since, -1, 1, true));
    $string = '';
    foreach ($since as $key => $val) {
        // separator
        if ($string) {
            $string .= $key != $last_key ? ', ' : ' ' . $lang['and'] . ' ';
        }
        // set plural
        $key .= $val > 1 ? 's' : '';
        // add date value
        $string .= $val . ' ' . $lang[ $key ];
    }
    return $string;
}

Looks much better:

1 year, 2 months, 53 minutes and 1 second

Optionally use $level = 2 to shorten it as follows:

1 year and 2 months

Remove the $lang part if you need it only in English or edit this translation to fit your needs:

$lang = array(
    'second' => 'Sekunde',
    'seconds' => 'Sekunden',
    'minute' => 'Minute',
    'minutes' => 'Minuten',
    'hour' => 'Stunde',
    'hours' => 'Stunden',
    'day' => 'Tag',
    'days' => 'Tage',
    'month' => 'Monat',
    'months' => 'Monate',
    'year' => 'Jahr',
    'years' => 'Jahre',
    'and' => 'und',
);

Error 415 Unsupported Media Type: POST not reaching REST if JSON, but it does if XML

Don't return Strings in your methods but Customer objects it self and let JAXB take care of the de/serialization.

XAMPP on Windows - Apache not starting

I had my Apache service not start same as MySQL one. Please follow these steps if none of above tips works :

Open regedit.exe on any windows this available . Run as administrator. (Only on windows 7 and later editions )
1. Go to local machine/system/controlset001/services
2. Find and delete folders of services apache and mysql .
3. Uninstall xampp . Delete folder of xampp.
4. Restart computer and reinstall Xampp . After that your Xampp apache and Mysql should work.

Note: Ports 80 and 443 must be unused by any program. 
      If it is in use . Just edit ports. There is a lot of tutorials about that .

Syntax for a single-line Bash infinite while loop

You don't even need to use do and done. For infinite loops I find it more readable to use for with curly brackets. For example:

for ((;;)) { date ; sleep 1 ; }

This works in bash and zsh. Doesn't work in sh.

Adding elements to object

cart.push({"element":{ id: id, quantity: quantity }});

Initializing IEnumerable<string> In C#

IEnumerable is an interface, instead of looking for how to create an interface instance, create an implementation that matches the interface: create a list or an array.

IEnumerable<string> myStrings = new [] { "first item", "second item" };
IEnumerable<string> myStrings = new List<string> { "first item", "second item" };

Select All distinct values in a column using LINQ

var uniq = allvalues.GroupBy(x => x.Id).Select(y=>y.First()).Distinct();

Easy and simple

Django download a file

I've found Django's FileField to be really helpful for letting users upload and download files. The Django documentation has a section on managing files. You can store some information about the file in a table, along with a FileField that points to the file itself. Then you can list the available files by searching the table.

Git: which is the default configured remote for branch?

For the sake of completeness: the previous answers tell how to set the upstream branch, but not how to see it.

There are a few ways to do this:

git branch -vv shows that info for all branches. (formatted in blue in most terminals)

cat .git/config shows this also.

For reference:

CSS I want a div to be on top of everything

I gonna assumed you making a popup with code from WW3 school, correct? check it css. the .modal one, there're already word z-index there. just change from 1 to 100.

.modal {
    display: none; /* Hidden by default */
    position: fixed; /* Stay in place */
    z-index: 1; /* Sit on top */
    padding-top: 100px; /* Location of the box */
    left: 0;
    top: 0;
    width: 100%; /* Full width */
    height: 100%; /* Full height */
    overflow: auto; /* Enable scroll if needed */
    background-color: rgb(0,0,0); /* Fallback color */
    background-color: rgba(0,0,0,0.4); /* Black w/ opacity */
}

How to loop backwards in python?

To reverse a string without using reversed or [::-1], try something like:

def reverse(text):
    # Container for reversed string
    txet=""

    # store the length of the string to be reversed
    # account for indexes starting at 0
    length = len(text)-1

    # loop through the string in reverse and append each character
    # deprecate the length index
    while length>=0:
        txet += "%s"%text[length]
        length-=1
    return txet

What is .htaccess file?

You can think it like php.ini files sub files.. php.ini file stores most of the configuration about php like curl enable disable. Where .htaccess makes this setting only for perticular directory and php.ini file store settings for its server' all directory...

Format number to always show 2 decimal places

parseInt(number * 100) / 100; worked for me.

Change default icon

If your designated icon shows when you run the EXE but not when you run it from Visual Studio, then, for a WPF project add the following at the top of your XAML: Icon="Images\MyIcon.ico". Put this just where you have the Title, and xmlns definitions. (Assuming you have an Images folder in your project, and that you added MyIcon.ico there).

Create Elasticsearch curl query for not null and not empty("")

Here's the query example to check the existence of multiple fields:

{
  "query": {
    "bool": {
      "filter": [
        {
          "exists": {
            "field": "field_1"
          }
        },
        {
          "exists": {
            "field": "field_2"
          }
        },
        {
          "exists": {
            "field": "field_n"
          }
        }
      ]
    }
  }
}

Delete keychain items when an app is uninstalled

There is no trigger to perform code when the app is deleted from the device. Access to the keychain is dependant on the provisioning profile that is used to sign the application. Therefore no other applications would be able to access this information in the keychain.

It does not help with you aim to remove the password in the keychain when the user deletes application from the device but it should give you some comfort that the password is not accessible (only from a re-install of the original application).

Disabling same-origin policy in Safari

Unfortunately, there is no equivalent for Safari and the argument --disable-web-security doesn't work with Safari.

If you have access to the server side application, you can modify the https response headers to allow access. Mainly the Access-Control-Allow-Origin header. Modifying it will allow Safari to access the resource. See https://developer.mozilla.org/en-US/docs/Web/HTTP/Access_control_CORS#Access-Control-Allow-Origin for more information on the response headers that will help.

Speed tradeoff of Java's -Xms and -Xmx options

> C:\java -X

-Xmixed           mixed mode execution (default)
-Xint             interpreted mode execution only
-Xbootclasspath:<directories and zip/jar files separated by ;>
                  set search path for bootstrap classes and resources
-Xbootclasspath/a:<directories and zip/jar files separated by ;>
                  append to end of bootstrap class path
-Xbootclasspath/p:<directories and zip/jar files separated by ;>
                  prepend in front of bootstrap class path
-Xnoclassgc       disable class garbage collection
-Xincgc           enable incremental garbage collection
-Xloggc:<file>    log GC status to a file with time stamps
-Xbatch           disable background compilation
-Xms<size>        set initial Java heap size
-Xmx<size>        set maximum Java heap size
-Xss<size>        set java thread stack size
-Xprof            output cpu profiling data
-Xfuture          enable strictest checks, anticipating future default
-Xrs              reduce use of OS signals by Java/VM (see documentation)
-Xcheck:jni       perform additional checks for JNI functions
-Xshare:off       do not attempt to use shared class data
-Xshare:auto      use shared class data if possible (default)
-Xshare:on        require using shared class data, otherwise fail.

The -X options are non-standard and subject to change without notice.

(copy-paste)

Getting list of tables, and fields in each, in a database

SELECT * FROM INFORMATION_SCHEMA.COLUMNS

When should I use Memcache instead of Memcached?

Memcached is a newer API, it also provides memcached as a session provider which could be great if you have a farm of server.

After the version is still really low 0.2 but I have used both and I didn't encounter major problem, so I would go to memcached since it's new.

Create a date from day month and year with T-SQL

Try CONVERT instead of CAST.

CONVERT allows a third parameter indicating the date format.

List of formats is here: http://msdn.microsoft.com/en-us/library/ms187928.aspx

Update after another answer has been selected as the "correct" answer:

I don't really understand why an answer is selected that clearly depends on the NLS settings on your server, without indicating this restriction.

ASP.NET MVC Html.DropDownList SelectedValue

You can still name the DropDown as "UserId" and still have model binding working correctly for you.

The only requirement for this to work is that the ViewData key that contains the SelectList does not have the same name as the Model property that you want to bind. In your specific case this would be:

// in my controller
ViewData["Users"] = new SelectList(
    users, 
    "UserId", 
    "DisplayName", 
    selectedUserId.Value); // this has a value

// in my view
<%=Html.DropDownList("UserId", (SelectList)ViewData["Users"])%>

This will produce a select element that is named UserId, which has the same name as the UserId property in your model and therefore the model binder will set it with the value selected in the html's select element generated by the Html.DropDownList helper.

I'm not sure why that particular Html.DropDownList constructor won't select the value specified in the SelectList when you put the select list in the ViewData with a key equal to the property name. I suspect it has something to do with how the DropDownList helper is used in other scenarios, where the convention is that you do have a SelectList in the ViewData with the same name as the property in your model. This will work correctly:

// in my controller
ViewData["UserId"] = new SelectList(
    users, 
    "UserId", 
    "DisplayName", 
    selectedUserId.Value); // this has a value

// in my view
<%=Html.DropDownList("UserId")%>

CSS show div background image on top of other contained elements

How about making the <div id="mainWrapperDivWithBGImage"> as three divs, where the two outside divs hold the rounded corners images, and the middle div simply has a background-color to match the rounded corner images. Then you could simply place the other elements inside the middle div, or:

#outside_left{width:10px; float:left;}
#outside_right{width:10px; float:right;}
#middle{background-color:#color of rnd_crnrs_foo.gif; float:left;}

Then

HTML:

<div id="mainWrapperDivWithBGImage">
  <div id="outside_left><img src="rnd_crnrs_left.gif" /></div>
  <div id="middle">
    <div id="another_div"><img src="foo.gif" /></div>
  <div id="outside_right><img src="rnd_crnrs_right.gif" /></div>
</div>

You may have to do position:relative; and such.

typeof operator in C

It's a GNU extension. In a nutshell it's a convenient way to declare an object having the same type as another. For example:

int x;         /* Plain old int variable. */
typeof(x) y;   /* Same type as x. Plain old int variable. */

~~It works entirely at compile-time~~ and it's primarily used in macros. One famous example of macro relying on typeof is container_of.

How to create a simple map using JavaScript/JQuery

var map = {'myKey1':myObj1, 'mykey2':myObj2};
// You don't need any get function, just use
map['mykey1']

Angular 2 'component' is not a known element

These are the 5 steps I perform when I got such an error.

Are you sure the name is correct? (also check the selector defined in the component)
Declare the component in a module?
If it is in another module, export the component?
If it is in another module, import that module?
Restart the cli?

When the error eccors during unit testing, make sure your declared the component or imported the module in TestBed.configureTestingModule

I also tried putting ContactBoxComponent in CustomersAddComponent and then in another one (from different module) but I got an error saying there are multiple declarations.

You can't declare a component twice. You should declare and export your component in a new separate module. Next you should import this new module in every module you want to use your component.

It is hard to tell when you should create new module and when you shouldn't. I usually create a new module for every component I reuse. When I have some components that I use almost everywhere I put them in a single module. When I have a component that I don't reuse I won't create a separate module until I need it somewhere else.

Though it might be tempting to put all you components in a single module, this is bad for the performance. While developing, a module has to recompile every time changes are made. The bigger the module (more components) the more time it takes. Making a small change to big module takes more time than making a small change in a small module.

Jquery Ajax beforeSend and success,error & complete

Maybe you can try the following :

var i = 0;
function AjaxSendForm(url, placeholder, form, append) {
var data = $(form).serialize();
append = (append === undefined ? false : true); // whatever, it will evaluate to true or false only
$.ajax({
    type: 'POST',
    url: url,
    data: data,
    beforeSend: function() {
        // setting a timeout
        $(placeholder).addClass('loading');
        i++;
    },
    success: function(data) {
        if (append) {
            $(placeholder).append(data);
        } else {
            $(placeholder).html(data);
        }
    },
    error: function(xhr) { // if error occured
        alert("Error occured.please try again");
        $(placeholder).append(xhr.statusText + xhr.responseText);
        $(placeholder).removeClass('loading');
    },
    complete: function() {
        i--;
        if (i <= 0) {
            $(placeholder).removeClass('loading');
        }
    },
    dataType: 'html'
});
}

This way, if the beforeSend statement is called before the complete statement i will be greater than 0 so it will not remove the class. Then only the last call will be able to remove it.

I cannot test it, let me know if it works or not.

How to rotate portrait/landscape Android emulator?

Yes. Thanks

Ctrl + F11 for Portrait

and

Ctrl + F12 for Landscape

Using async/await for multiple tasks

I was curious to see the results of the methods provided in the question as well as the accepted answer, so I put it to the test.

Here's the code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;

namespace AsyncTest
{
    class Program
    {
        class Worker
        {
            public int Id;
            public int SleepTimeout;

            public async Task DoWork(DateTime testStart)
            {
                var workerStart = DateTime.Now;
                Console.WriteLine("Worker {0} started on thread {1}, beginning {2} seconds after test start.",
                    Id, Thread.CurrentThread.ManagedThreadId, (workerStart-testStart).TotalSeconds.ToString("F2"));
                await Task.Run(() => Thread.Sleep(SleepTimeout));
                var workerEnd = DateTime.Now;
                Console.WriteLine("Worker {0} stopped; the worker took {1} seconds, and it finished {2} seconds after the test start.",
                   Id, (workerEnd-workerStart).TotalSeconds.ToString("F2"), (workerEnd-testStart).TotalSeconds.ToString("F2"));
            }
        }

        static void Main(string[] args)
        {
            var workers = new List<Worker>
            {
                new Worker { Id = 1, SleepTimeout = 1000 },
                new Worker { Id = 2, SleepTimeout = 2000 },
                new Worker { Id = 3, SleepTimeout = 3000 },
                new Worker { Id = 4, SleepTimeout = 4000 },
                new Worker { Id = 5, SleepTimeout = 5000 },
            };

            var startTime = DateTime.Now;
            Console.WriteLine("Starting test: Parallel.ForEach...");
            PerformTest_ParallelForEach(workers, startTime);
            var endTime = DateTime.Now;
            Console.WriteLine("Test finished after {0} seconds.\n",
                (endTime - startTime).TotalSeconds.ToString("F2"));

            startTime = DateTime.Now;
            Console.WriteLine("Starting test: Task.WaitAll...");
            PerformTest_TaskWaitAll(workers, startTime);
            endTime = DateTime.Now;
            Console.WriteLine("Test finished after {0} seconds.\n",
                (endTime - startTime).TotalSeconds.ToString("F2"));

            startTime = DateTime.Now;
            Console.WriteLine("Starting test: Task.WhenAll...");
            var task = PerformTest_TaskWhenAll(workers, startTime);
            task.Wait();
            endTime = DateTime.Now;
            Console.WriteLine("Test finished after {0} seconds.\n",
                (endTime - startTime).TotalSeconds.ToString("F2"));

            Console.ReadKey();
        }

        static void PerformTest_ParallelForEach(List<Worker> workers, DateTime testStart)
        {
            Parallel.ForEach(workers, worker => worker.DoWork(testStart).Wait());
        }

        static void PerformTest_TaskWaitAll(List<Worker> workers, DateTime testStart)
        {
            Task.WaitAll(workers.Select(worker => worker.DoWork(testStart)).ToArray());
        }

        static Task PerformTest_TaskWhenAll(List<Worker> workers, DateTime testStart)
        {
            return Task.WhenAll(workers.Select(worker => worker.DoWork(testStart)));
        }
    }
}

And the resulting output:

Starting test: Parallel.ForEach...
Worker 1 started on thread 1, beginning 0.21 seconds after test start.
Worker 4 started on thread 5, beginning 0.21 seconds after test start.
Worker 2 started on thread 3, beginning 0.21 seconds after test start.
Worker 5 started on thread 6, beginning 0.21 seconds after test start.
Worker 3 started on thread 4, beginning 0.21 seconds after test start.
Worker 1 stopped; the worker took 1.90 seconds, and it finished 2.11 seconds after the test start.
Worker 2 stopped; the worker took 3.89 seconds, and it finished 4.10 seconds after the test start.
Worker 3 stopped; the worker took 5.89 seconds, and it finished 6.10 seconds after the test start.
Worker 4 stopped; the worker took 5.90 seconds, and it finished 6.11 seconds after the test start.
Worker 5 stopped; the worker took 8.89 seconds, and it finished 9.10 seconds after the test start.
Test finished after 9.10 seconds.

Starting test: Task.WaitAll...
Worker 1 started on thread 1, beginning 0.01 seconds after test start.
Worker 2 started on thread 1, beginning 0.01 seconds after test start.
Worker 3 started on thread 1, beginning 0.01 seconds after test start.
Worker 4 started on thread 1, beginning 0.01 seconds after test start.
Worker 5 started on thread 1, beginning 0.01 seconds after test start.
Worker 1 stopped; the worker took 1.00 seconds, and it finished 1.01 seconds after the test start.
Worker 2 stopped; the worker took 2.00 seconds, and it finished 2.01 seconds after the test start.
Worker 3 stopped; the worker took 3.00 seconds, and it finished 3.01 seconds after the test start.
Worker 4 stopped; the worker took 4.00 seconds, and it finished 4.01 seconds after the test start.
Worker 5 stopped; the worker took 5.00 seconds, and it finished 5.01 seconds after the test start.
Test finished after 5.01 seconds.

Starting test: Task.WhenAll...
Worker 1 started on thread 1, beginning 0.00 seconds after test start.
Worker 2 started on thread 1, beginning 0.00 seconds after test start.
Worker 3 started on thread 1, beginning 0.00 seconds after test start.
Worker 4 started on thread 1, beginning 0.00 seconds after test start.
Worker 5 started on thread 1, beginning 0.00 seconds after test start.
Worker 1 stopped; the worker took 1.00 seconds, and it finished 1.00 seconds after the test start.
Worker 2 stopped; the worker took 2.00 seconds, and it finished 2.00 seconds after the test start.
Worker 3 stopped; the worker took 3.00 seconds, and it finished 3.00 seconds after the test start.
Worker 4 stopped; the worker took 4.00 seconds, and it finished 4.00 seconds after the test start.
Worker 5 stopped; the worker took 5.00 seconds, and it finished 5.00 seconds after the test start.
Test finished after 5.00 seconds.

iPhone Navigation Bar Title text color

You should call [label sizeToFit]; after setting the text to prevent strange offsets when the label is automatically repositioned in the title view when other buttons occupy the nav bar.

Change image in HTML page every few seconds

Change setTimeout("changeImage()", 30000); to setInterval("changeImage()", 30000); and remove var timerid = setInterval(changeImage, 30000);.

Can I pass column name as input parameter in SQL stored Procedure

No. That would just select the parameter value. You would need to use dynamic sql.

In your procedure you would have the following:

DECLARE @sql nvarchar(max) = 'SELECT ' + @columnname + ' FROM Table_1';
exec sp_executesql @sql, N''

How to add 'ON DELETE CASCADE' in ALTER TABLE statement

You can not add ON DELETE CASCADE to an already existing constraint. You will have to drop and re-create the constraint. The documentation shows that the MODIFY CONSTRAINT clause can only modify the state of a constraint (i-e: ENABLED/DISABLED...).

Zsh: Conda/Pip installs command not found

run the following script provided by conda in your terminal:

source /opt/conda/etc/profile.d/conda.sh - you may need to adjust the path to your conda installtion folder.

after that your zsh will recognize conda and you can run conda init this will modify your .zshrc file automatically for you. It will add something like that at the end of it:

# >>> conda initialize >>>
# !! Contents within this block are managed by 'conda init' !!
__conda_setup="$('/opt/conda/bin/conda' 'shell.zsh' 'hook' 2> /dev/null)"
if [ $? -eq 0 ]; then
    eval "$__conda_setup"
else
    if [ -f "/opt/conda/etc/profile.d/conda.sh" ]; then
        . "/opt/conda/etc/profile.d/conda.sh"
    else
        export PATH="/opt/conda/bin:$PATH"
    fi
fi
unset __conda_setup
# <<< conda initialize <<<

source: https://docs.conda.io/projects/conda/en/latest/user-guide/install/rpm-debian.html

how to access iFrame parent page using jquery?

It's working for me with little twist. In my case I have to populate value from POPUP JS to PARENT WINDOW form.

So I have used $('#ee_id',window.opener.document).val(eeID);

Excellent!!!

Error LNK2019 unresolved external symbol _main referenced in function "int __cdecl invoke_main(void)" (?invoke_main@@YAHXZ)

Solution for me is: I clean both the solution and the project. And just rebuild the project. This error happens because I tried to delete the main file (only keep library files) in the previous build so at the current build the old stuff is still kept in the built directory. That's why unresolved things happened. "unresolved external symbol _main referenced in function "int __cdecl invoke_main(void)" (?invoke_main@@YAHXZ) "

How to check whether java is installed on the computer

Check the installation directories (typically C:\Program Files (x86) or C:\Program Files) for the java folder. If it contains the JRE you have java installed.

Code to loop through all records in MS Access

You should be able to do this with a pretty standard DAO recordset loop. You can see some examples at the following links:
http://msdn.microsoft.com/en-us/library/bb243789%28v=office.12%29.aspx
http://www.granite.ab.ca/access/email/recordsetloop.htm

My own standard loop looks something like this:

Dim rs As DAO.Recordset
Set rs = CurrentDb.OpenRecordset("SELECT * FROM Contacts")

'Check to see if the recordset actually contains rows
If Not (rs.EOF And rs.BOF) Then
    rs.MoveFirst 'Unnecessary in this case, but still a good habit
    Do Until rs.EOF = True
        'Perform an edit
        rs.Edit
        rs!VendorYN = True
        rs("VendorYN") = True 'The other way to refer to a field
        rs.Update

        'Save contact name into a variable
        sContactName = rs!FirstName & " " & rs!LastName

        'Move to the next record. Don't ever forget to do this.
        rs.MoveNext
    Loop
Else
    MsgBox "There are no records in the recordset."
End If

MsgBox "Finished looping through records."

rs.Close 'Close the recordset
Set rs = Nothing 'Clean up

Error occurred during initialization of VM (java/lang/NoClassDefFoundError: java/lang/Object)

Go to Eclipse folder, locate eclipse.ini file, add following entry (before -vmargs if present):

-vm
C:\Program Files\Java\jdk1.7.0_10\bin\javaw.exe

Save file and execute eclipse.exe.

What does on_delete do on Django models?

Deletes all child fields in the database then we use on_delete as so:

class user(models.Model):
 commodities = models.ForeignKey(commodity, on_delete=models.CASCADE)

Android Gallery on Android 4.4 (KitKat) returns different URI for Intent.ACTION_GET_CONTENT

For those who is still using @Paul Burke's code with Android SDK version 23 and above, if your project met the error saying that you are missing EXTERNAL_PERMISSION, and you are very sure you have already added user-permission in your AndroidManifest.xml file. That's because you may in Android API 23 or above and Google make it necessary to guarantee permission again while you make the action to access the file in runtime.

That means: If your SDK version is 23 or above, you are asked for READ & WRITE permission while you are selecting the picture file and want to know the URI of it.

And following is my code, in addition to Paul Burke's solution. I add these code and my project start to work fine.

private static final int REQUEST_EXTERNAL_STORAGE = 1;
private static final String[] PERMISSINOS_STORAGE = {
    Manifest.permission.READ_EXTERNAL_STORAGE,
    Manifest.permission.WRITE_EXTERNAL_STORAGE
};

public static void verifyStoragePermissions(Activity activity) {
    int permission = ActivityCompat.checkSelfPermission(activity, Manifest.permission.WRITE_EXTERNAL_STORAGE);

    if (permission != PackageManager.PERMISSION_GRANTED) {
        ActivityCompat.requestPermissions(
                activity,
                PERMISSINOS_STORAGE,
                REQUEST_EXTERNAL_STORAGE
        );
    }
}

And in your activity&fragment where you are asking for the URI:

private void pickPhotoFromGallery() {

    CompatUtils.verifyStoragePermissions(this);
    Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
    intent.setType("image/*");
    // startActivityForResult(intent, REQUEST_PHOTO_LIBRARY);
    startActivityForResult(Intent.createChooser(intent, "????"),
            REQUEST_PHOTO_LIBRARY);
}

In my case, CompatUtils.java is where I define the verifyStoragePermissions method (as static type so I can call it within other activity).

Also it should make more sense if you make an if state first to see whether the current SDK version is above 23 or not before you call the verifyStoragePermissions method.

Delete file from internal storage

Have you tried getFilesDir().getAbsolutePath()?

Seems you fixed your problem by initializing the File object with a full path. I believe this would also do the trick.

What is the reason for java.lang.IllegalArgumentException: No enum const class even though iterating through values() works just fine?

I had parsing enum problem when i was trying to pass Nullable Enum that we get from Backend. Of course it was working when we get value, but it was problem when the null comes up.

java.lang.IllegalArgumentException: No enum constant

Also the problem was when we at Parcelize read moment write some short if.

My solution for this was

1.Create companion object with parsing method.

enum class CarsType {
    @Json(name = "SMALL")
    SMALL,
    @Json(name = "BIG")
    BIG;

    companion object {
        fun nullableValueOf(name: String?) = when (name) {
            null -> null
            else -> valueOf(name)
        }
    }
}

2. In Parcerable read place use it like this

data class CarData(
    val carId: String? = null,
    val carType: CarsType?,
    val data: String?
) : Parcelable {
    constructor(parcel: Parcel) : this(
        parcel.readString(),
        CarsType.nullableValueOf(parcel.readString()),
        parcel.readString())

How can a Javascript object refer to values in itself?

Maybe you can think about removing the attribute to a function. I mean something like this:

_x000D_

var obj = {_x000D_
  key1: "it ",_x000D_
  key2: function() {_x000D_
    return this.key1 + " works!";_x000D_
  }_x000D_
};_x000D_
_x000D_
alert(obj.key2());

_x000D_

rebase in progress. Cannot commit. How to proceed or stop (abort)?

Another option to ABORT / SKIP / CONTINUE from IDE

VCS > Git > Abort Rebasing

How to attach a process in gdb

With a running instance of myExecutableName having a PID 15073:

hitting Tab twice after $ gdb myExecu in the command line, will automagically autocompletes to:

$ gdb myExecutableName 15073

and will attach gdb to this process. That's nice!

What tools do you use to test your public REST API?

I am using DevHttpClient Plugin for chrome, its handy. it does also saves previous actions. clean UI as well

How to call a Web Service Method?

In visual studio, use the "Add Web Reference" feature and then enter in the URL of your web service.

By adding a reference to the DLL, you not referencing it as a web service, but simply as an assembly.

When you add a web reference it create a proxy class in your project that has the same or similar methods/arguments as your web service. That proxy class communicates with your web service via SOAP but hides all of the communications protocol stuff so you don't have to worry about it.

How do you post to an iframe?

This function creates a temporary form, then send data using jQuery :

function postToIframe(data,url,target){
    $('body').append('<form action="'+url+'" method="post" target="'+target+'" id="postToIframe"></form>');
    $.each(data,function(n,v){
        $('#postToIframe').append('<input type="hidden" name="'+n+'" value="'+v+'" />');
    });
    $('#postToIframe').submit().remove();
}

target is the 'name' attr of the target iFrame, and data is a JS object :

data={last_name:'Smith',first_name:'John'}

Is 'bool' a basic datatype in C++?

Yes, C++ supports bool and it is a data type. For reference - Bool data type

Reading from memory stream to string

In case of a very large stream length there is the hazard of memory leak due to Large Object Heap. i.e. The byte buffer created by stream.ToArray creates a copy of memory stream in Heap memory leading to duplication of reserved memory. I would suggest to use a StreamReader, a TextWriter and read the stream in chunks of char buffers.

In netstandard2.0 System.IO.StreamReader has a method ReadBlock

you can use this method in order to read the instance of a Stream (a MemoryStream instance as well since Stream is the super of MemoryStream):

private static string ReadStreamInChunks(Stream stream, int chunkLength)
{
    stream.Seek(0, SeekOrigin.Begin);
    string result;
    using(var textWriter = new StringWriter())
    using (var reader = new StreamReader(stream))
    {
        var readChunk = new char[chunkLength];
        int readChunkLength;
        //do while: is useful for the last iteration in case readChunkLength < chunkLength
        do
        {
            readChunkLength = reader.ReadBlock(readChunk, 0, chunkLength);
            textWriter.Write(readChunk,0,readChunkLength);
        } while (readChunkLength > 0);

        result = textWriter.ToString();
    }

    return result;
}

NB. The hazard of memory leak is not fully eradicated, due to the usage of MemoryStream, that can lead to memory leak for large memory stream instance (memoryStreamInstance.Size >85000 bytes). You can use Recyclable Memory stream, in order to avoid LOH. This is the relevant library

Creating a JSON response using Django and Python

You'll want to use the django serializer to help with unicode stuff:

from django.core import serializers

json_serializer = serializers.get_serializer("json")()
    response =  json_serializer.serialize(list, ensure_ascii=False, indent=2, use_natural_keys=True)
    return HttpResponse(response, mimetype="application/json")

MongoDB vs. Cassandra

Why choose between a traditional database and a NoSQL data store? Use both! The problem with NoSQL solutions (beyond the initial learning curve) is the lack of transactions -- you do all updates to MySQL and have MySQL populate a NoSQL data store for reads -- you then benefit from each technology's strengths. This does add more complexity, but you already have the MySQL side -- just add MongoDB, Cassandra, etc to the mix.

NoSQL datastores generally scale way better than a traditional DB for the same otherwise specs -- there is a reason why Facebook, Twitter, Google, and most start-ups are using NoSQL solutions. It's not just geeks getting high on new tech.

How to install SQL Server Management Studio 2012 (SSMS) Express?

Easiest way to install MSSQL 2012 MS SQL INSTALLATION

Here i am showing the easiest way to install ms sql 2012.

My opinion is the installation will be easier with windows 8.1 rather than windows 7.

This is my personnal opinion only.

We can install in windows 7 as well.

The steps to be followed:

Download any one of the link using the following URL

http://www.microsoft.com/en-us/download/details.aspx?id=43351

SQLEXPRWT_x86_ENU.exe or SQLEXPRWT_x64_ENU.exe

http://www.microsoft.com/en-us/download/details.aspx?id=42299

SQLEXPRWT_x86_ENU.exe or SQLEXPRWT_x64_ENU.exe

Right click on .exe file and run it

We should leave everything default while installing.

During installation, there will be 2 options:

1)If you are New user,then click on new sql-server stand alone application.

2)If you have already MS SQL application then you can upgrade by using the other option.

Then accept the Licence terms and click Next.

Now you will move on to Product Updates and press next then Setup support rules.

After this Feature selection.According to me we can check all the boxes except localdb.

Next it will take you to Instance Configuration where you should select Named Instance as

"SQLEXPRESS".

Then go to Server Configuration and press next.

Now Database engine configuration:

Authentication Mode:we can click on any one that is windows authentication mode or mixed.

Windows authentication mode (default for windows).

Mixed authentication mode:then should create username and password.

Then move on Error reporting,we can move further by clicking next to install process.

Finally we can see the Complete windows by showing the products added .

We can close and run the MSSQL server.

I hope it's useful.

Regards

Ramya

Replacing Spaces with Underscores

$name = str_replace(' ', '_', $name);

How to create a shared library with cmake?

Always specify the minimum required version of cmake

cmake_minimum_required(VERSION 3.9)

You should declare a project. cmake says it is mandatory and it will define convenient variables PROJECT_NAME, PROJECT_VERSION and PROJECT_DESCRIPTION (this latter variable necessitate cmake 3.9):

project(mylib VERSION 1.0.1 DESCRIPTION "mylib description")

Declare a new library target. Please avoid the use of file(GLOB ...). This feature does not provide attended mastery of the compilation process. If you are lazy, copy-paste output of ls -1 sources/*.cpp :

add_library(mylib SHARED
    sources/animation.cpp
    sources/buffers.cpp
    [...]
)

Set VERSION property (optional but it is a good practice):

set_target_properties(mylib PROPERTIES VERSION ${PROJECT_VERSION})

You can also set SOVERSION to a major number of VERSION. So libmylib.so.1 will be a symlink to libmylib.so.1.0.0.

set_target_properties(mylib PROPERTIES SOVERSION 1)

Declare public API of your library. This API will be installed for the third-party application. It is a good practice to isolate it in your project tree (like placing it include/ directory). Notice that, private headers should not be installed and I strongly suggest to place them with the source files.

set_target_properties(mylib PROPERTIES PUBLIC_HEADER include/mylib.h)

If you work with subdirectories, it is not very convenient to include relative paths like "../include/mylib.h". So, pass a top directory in included directories:

target_include_directories(mylib PRIVATE .)

target_include_directories(mylib PRIVATE include)
target_include_directories(mylib PRIVATE src)

Create an install rule for your library. I suggest to use variables CMAKE_INSTALL_*DIR defined in GNUInstallDirs:

include(GNUInstallDirs)

And declare files to install:

install(TARGETS mylib
    LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
    PUBLIC_HEADER DESTINATION ${CMAKE_INSTALL_INCLUDEDIR})

You may also export a pkg-config file. This file allows a third-party application to easily import your library:

with Makefile, see pkg-config
with Autotools, see PKG_CHECK_MODULES
with cmake, see pkg_check_modules

Create a template file named mylib.pc.in (see pc(5) manpage for more information):

prefix=@CMAKE_INSTALL_PREFIX@
exec_prefix=@CMAKE_INSTALL_PREFIX@
libdir=${exec_prefix}/@CMAKE_INSTALL_LIBDIR@
includedir=${prefix}/@CMAKE_INSTALL_INCLUDEDIR@

Name: @PROJECT_NAME@
Description: @PROJECT_DESCRIPTION@
Version: @PROJECT_VERSION@

Requires:
Libs: -L${libdir} -lmylib
Cflags: -I${includedir}

In your CMakeLists.txt, add a rule to expand @ macros (@ONLY ask to cmake to not expand variables of the form ${VAR}):

configure_file(mylib.pc.in mylib.pc @ONLY)

And finally, install generated file:

install(FILES ${CMAKE_BINARY_DIR}/mylib.pc DESTINATION ${CMAKE_INSTALL_DATAROOTDIR}/pkgconfig)

You may also use cmake EXPORT feature. However, this feature is only compatible with cmake and I find it difficult to use.

Finally the entire CMakeLists.txt should looks like:

cmake_minimum_required(VERSION 3.9)
project(mylib VERSION 1.0.1 DESCRIPTION "mylib description")
include(GNUInstallDirs)
add_library(mylib SHARED src/mylib.c)
set_target_properties(mylib PROPERTIES
    VERSION ${PROJECT_VERSION}
    SOVERSION 1
    PUBLIC_HEADER api/mylib.h)
configure_file(mylib.pc.in mylib.pc @ONLY)
target_include_directories(mylib PRIVATE .)
install(TARGETS mylib
    LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
    PUBLIC_HEADER DESTINATION ${CMAKE_INSTALL_INCLUDEDIR})
install(FILES ${CMAKE_BINARY_DIR}/mylib.pc
    DESTINATION ${CMAKE_INSTALL_DATAROOTDIR}/pkgconfig)

how to prevent this error : Warning: mysql_fetch_assoc() expects parameter 1 to be resource, boolean given in ... on line 11

If you just want to suppress warnings from a function, you can add an @ sign in front:

<?php @function_that_i_dont_want_to_see_errors_from(parameters); ?>

Remove last character from C++ string

str.erase( str.end()-1 )

Reference: std::string::erase() prototype 2

no c++11 or c++0x needed.

Mocking python function based on input arguments

Although side_effect can achieve the goal, it is not so convenient to setup side_effect function for each test case.

I write a lightweight Mock (which is called NextMock) to enhance the built-in mock to address this problem, here is a simple example:

from nextmock import Mock

m = Mock()

m.with_args(1, 2, 3).returns(123)

assert m(1, 2, 3) == 123
assert m(3, 2, 1) != 123

It also supports argument matcher:

from nextmock import Arg, Mock

m = Mock()

m.with_args(1, 2, Arg.Any).returns(123)

assert m(1, 2, 1) == 123
assert m(1, 2, "123") == 123

Hope this package could make testing more pleasant. Feel free to give any feedback.

Extract only right most n letters from a string

MSDN

String mystr = "PER 343573";
String number = mystr.Substring(mystr.Length-6);

EDIT: too slow...

GCC fatal error: stdio.h: No such file or directory

I had the same problem. I installed "XCode: development tools" from the app store and it fixed the problem for me.

I think this link will help: https://itunes.apple.com/us/app/xcode/id497799835?mt=12&ls=1

Credit to Yann Ramin for his advice. I think there is a better solution with links, but this was easy and fast.

Good luck!

How to center a component in Material-UI and make it responsive?

You can do this with the Box component:

import Box from "@material-ui/core/Box";

...

<Box
  display="flex"
  justifyContent="center"
  alignItems="center"
  minHeight="100vh"
>
  <YourComponent/>
</Box>

redirect COPY of stdout to log file from within bash script itself

#!/usr/bin/env bash

# Redirect stdout ( > ) into a named pipe ( >() ) running "tee"
exec > >(tee -i logfile.txt)

# Without this, only stdout would be captured - i.e. your
# log file would not contain any error messages.
# SEE (and upvote) the answer by Adam Spiers, which keeps STDERR
# as a separate stream - I did not want to steal from him by simply
# adding his answer to mine.
exec 2>&1

echo "foo"
echo "bar" >&2

Note that this is bash, not sh. If you invoke the script with sh myscript.sh, you will get an error along the lines of syntax error near unexpected token '>'.

If you are working with signal traps, you might want to use the tee -i option to avoid disruption of the output if a signal occurs. (Thanks to JamesThomasMoon1979 for the comment.)

Tools that change their output depending on whether they write to a pipe or a terminal (ls using colors and columnized output, for example) will detect the above construct as meaning that they output to a pipe.

There are options to enforce the colorizing / columnizing (e.g. ls -C --color=always). Note that this will result in the color codes being written to the logfile as well, making it less readable.

How do I download the Android SDK without downloading Android Studio?

I downloaded Android Studio and installed it. The installer said:-

Android Studio => ( 500 MB )

Android SDK => ( 2.3 GB )

Android Studio installer is actually an "Android SDK Installer" along with a sometimes useful tool called "Android Studio".

Most importantly:- Android Studio Installer will not just install the SDK. It will also:-

Install the latest build-tools.
Install the latest platform-tools.
Install the latest AVD Manager which you cannot do without.

Things which you will have to do manually if you install the SDK from its zip file.

Just take it easy. Install the Android Studio.

****************************** Edit ******************************

So, being inspired by the responses in the comments I would like to update my answer.

The update is that only (and only) if 500MB of hard disk space does not matter much to you than you should go for Android Studio otherwise other answers would be better for you.

Android Studio worked for me as I had a 1TB hard disk which is 2000 times 500MB.

Also, note: that RAM sizse should not a restriction for you as you would not even be running Android Studio.

I came to this solution as I was myself stuck in this problem. I tried other answers but for some reason (maybe my in-competencies) they did not work for me. I decided to go for Android Studio and realized that it was merely 18% of the total installation and SDK was 82% of it. While I used to think otherwise. I am not deleting the answers inspite of negative rating as the answer worked for me. I might work for someone elese with a 1 TB hard disk (which is pretty common these days).

Oracle: If Table Exists

BEGIN
   EXECUTE IMMEDIATE 'DROP TABLE "IMS"."MAX" ';
EXCEPTION
   WHEN OTHERS THEN
      IF SQLCODE != -942 THEN
         RAISE;
          END IF;
         EXECUTE IMMEDIATE ' 
  CREATE TABLE "IMS"."MAX" 
   (    "ID" NUMBER NOT NULL ENABLE, 
    "NAME" VARCHAR2(20 BYTE), 
     CONSTRAINT "MAX_PK" PRIMARY KEY ("ID")
  USING INDEX PCTFREE 10 INITRANS 2 MAXTRANS 255 
  STORAGE(INITIAL 65536 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645
  PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT)
  TABLESPACE "SYSAUX"  ENABLE
   ) SEGMENT CREATION IMMEDIATE 
  PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255 NOCOMPRESS LOGGING
  STORAGE(INITIAL 65536 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645
  PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT)
  TABLESPACE "SYSAUX"  ';


END;

// Doing this code, checks if the table exists and later it creates the table max. this simply works in single compilation

Output array to CSV in Ruby

If you have an array of arrays of data:

rows = [["a1", "a2", "a3"],["b1", "b2", "b3", "b4"], ["c1", "c2", "c3"]]

Then you can write this to a file with the following, which I think is much simpler:

require "csv"
File.write("ss.csv", rows.map(&:to_csv).join)

Parsing CSV / tab-delimited txt file with Python

Start by turning the text into a list of lists. That will take care of the parsing part:

lol = list(csv.reader(open('text.txt', 'rb'), delimiter='\t'))

The rest can be done with indexed lookups:

d = dict()
key = lol[6][0]      # cell A7
value = lol[6][3]    # cell D7
d[key] = value       # add the entry to the dictionary
 ...

getMinutes() 0-9 - How to display two digit numbers?

I assume you would need the value as string. You could use the code below. It will always return give you the two digit minutes as string.

var date = new Date(date);
var min = date.getMinutes();

if (min < 10) {
min = '0' + min;
} else {
min = min + '';
}
console.log(min);

Hope this helps.

No ConcurrentList<T> in .Net 4.0?

I gave it a try a while back (also: on GitHub). My implementation had some problems, which I won't get into here. Let me tell you, more importantly, what I learned.

Firstly, there's no way you're going to get a full implementation of IList<T> that is lockless and thread-safe. In particular, random insertions and removals are not going to work, unless you also forget about O(1) random access (i.e., unless you "cheat" and just use some sort of linked list and let the indexing suck).

What I thought might be worthwhile was a thread-safe, limited subset of IList<T>: in particular, one that would allow an Add and provide random read-only access by index (but no Insert, RemoveAt, etc., and also no random write access).

This was the goal of my ConcurrentList<T> implementation. But when I tested its performance in multithreaded scenarios, I found that simply synchronizing adds to a List<T> was faster. Basically, adding to a List<T> is lightning fast already; the complexity of the computational steps involved is miniscule (increment an index and assign to an element in an array; that's really it). You would need a ton of concurrent writes to see any sort of lock contention on this; and even then, the average performance of each write would still beat out the more expensive albeit lockless implementation in ConcurrentList<T>.

In the relatively rare event that the list's internal array needs to resize itself, you do pay a small cost. So ultimately I concluded that this was the one niche scenario where an add-only ConcurrentList<T> collection type would make sense: when you want guaranteed low overhead of adding an element on every single call (so, as opposed to an amortized performance goal).

It's simply not nearly as useful a class as you would think.

Display array values in PHP

Iterate over the array and do whatever you want with the individual values.

foreach ($array as $key => $value) {
    echo $key . ' contains ' . $value . '<br/>';
}

Return value of x = os.system(..)

os.system('command') returns a 16 bit number, which first 8 bits from left(lsb) talks about signal used by os to close the command, Next 8 bits talks about return code of command.

Refer my answer for more detail in What is the return value of os.system() in Python?

How to succinctly write a formula with many variables from a data frame?

An extension of juba's method is to use reformulate, a function which is explicitly designed for such a task.

## Create a formula for a model with a large number of variables:
xnam <- paste("x", 1:25, sep="")

reformulate(xnam, "y")
y ~ x1 + x2 + x3 + x4 + x5 + x6 + x7 + x8 + x9 + x10 + x11 + 
    x12 + x13 + x14 + x15 + x16 + x17 + x18 + x19 + x20 + x21 + 
    x22 + x23 + x24 + x25

For the example in the OP, the easiest solution here would be

# add y variable to data.frame d
d <- cbind(y, d)
reformulate(names(d)[-1], names(d[1]))
y ~ x1 + x2 + x3

mod <- lm(reformulate(names(d)[-1], names(d[1])), data=d)

Note that adding the dependent variable to the data.frame in d <- cbind(y, d) is preferred not only because it allows for the use of reformulate, but also because it allows for future use of the lm object in functions like predict.

Directly export a query to CSV using SQL Developer

After Ctrl+End, you can do the Ctrl+A to select all in the buffer and then paste into Excel. Excel even put each Oracle column into its own column instead of squishing the whole row into one column. Nice..

Android Studio emulator does not come with Play Store for API 23

Just want to add another solution for React Native users that just need the Expo app.

Install the Expo app
Open you project
Click Device -> Open on Android - In this stage Expo will install the expo android app and you'll be able to open it.

How to discard local changes in an SVN checkout?

concatenate variables

If you need to concatenate paths with quotes, you can use = to replace quotes in a variable. This does not require you to know if the path already contains quotes or not. If there are no quotes, nothing is changed.

@echo off
rem Paths to combine
set DIRECTORY="C:\Directory with spaces"
set FILENAME="sub directory\filename.txt"

rem Combine two paths
set COMBINED="%DIRECTORY:"=%\%FILENAME:"=%"
echo %COMBINED%

rem This is just to illustrate how the = operator works
set DIR_WITHOUT_SPACES=%DIRECTORY:"=%
echo %DIR_WITHOUT_SPACES%

How to create own dynamic type or dynamic object in C#?

ExpandoObject is what are you looking for.

dynamic MyDynamic = new ExpandoObject(); // note, the type MUST be dynamic to use dynamic invoking.
MyDynamic.A = "A";
MyDynamic.B = "B";
MyDynamic.C = "C";
MyDynamic.TheAnswerToLifeTheUniverseAndEverything = 42;

How to dump only specific tables from MySQL?

Usage: mysqldump [OPTIONS] database [tables]

i.e.

mysqldump -u username -p db_name table1_name table2_name table3_name > dump.sql

How to use vagrant in a proxy environment?

In MS Windows this works for us:

set http_proxy=< proxy_url >
set https_proxy=< proxy_url >

And the equivalent for *nix:

export http_proxy=< proxy_url >
export https_proxy=< proxy_url >

How to change button text or link text in JavaScript?

Remove Quote. and use innerText instead of text

function toggleText(button_id) 
{                      //-----\/ 'button_id' - > button_id
   if (document.getElementById(button_id).innerText == "Lock") 
   {
       document.getElementById(button_id).innerText = "Unlock";
   }
   else 
   {
     document.getElementById(button_id).innerText = "Lock";
   }
}

How to convert characters to HTML entities using plain JavaScript

Demo on JSFiddle

here's a tiny stand alone method that:

attempts to consolidate the answers on this page, without using a library
works in older browsers
supports surrogate pairs (like emojis)
applies character overrides (what's that? not sure exactly)

i don't know too much about unicode, but it seems to be working well.

// escape a string for display in html
// see also: 
// polyfill for String.prototype.codePointAt
//   https://raw.githubusercontent.com/mathiasbynens/String.prototype.codePointAt/master/codepointat.js
// how to convert characters to html entities
//     http://stackoverflow.com/a/1354491/347508
// html overrides from 
//   https://html.spec.whatwg.org/multipage/syntax.html#table-charref-overrides / http://stackoverflow.com/questions/1354064/how-to-convert-characters-to-html-entities-using-plain-javascript/23831239#comment36668052_1354098

var _escape_overrides = { 0x00:'\uFFFD',0x80:'\u20AC',0x82:'\u201A',0x83:'\u0192',0x84:'\u201E',0x85:'\u2026',0x86:'\u2020',0x87:'\u2021',0x88:'\u02C6',0x89:'\u2030',0x8A:'\u0160',0x8B:'\u2039',0x8C:'\u0152',0x8E:'\u017D',0x91:'\u2018',0x92:'\u2019',0x93:'\u201C',0x94:'\u201D',0x95:'\u2022',0x96:'\u2013',0x97:'\u2014',0x98:'\u02DC',0x99:'\u2122',0x9A:'\u0161',0x9B:'\u203A',0x9C:'\u0153',0x9E:'\u017E',0x9F:'\u0178' }; 

function escapeHtml(str){
    return str.replace(/([\u0000-\uD799]|[\uD800-\uDBFF][\uDC00-\uFFFF])/g, function(c) {
        var c1 = c.charCodeAt(0);
        // ascii character, use override or escape
        if( c1 <= 0xFF ) return (c1=_escape_overrides[c1])?c1:escape(c).replace(/%(..)/g,"&#x$1;");
        // utf8/16 character
        else if( c.length == 1 ) return "&#" + c1 + ";"; 
        // surrogate pair
        else if( c.length == 2 && c1 >= 0xD800 && c1 <= 0xDBFF ) return "&#" + ((c1-0xD800)*0x400 + c.charCodeAt(1) - 0xDC00 + 0x10000) + ";"
        // no clue .. 
        else return "";
    });
}

How to make --no-ri --no-rdoc the default for gem install?

You just add the following line to your local ~/.gemrc file (it is in your home folder):

gem: --no-document

or you can add this line to the global gemrc config file.

Here is how to find it (in Linux):

strace gem source 2>&1 | grep gemrc

"ImportError: no module named 'requests'" after installing with pip

if it works when you do :

python
>>> import requests

then it might be a mismatch between a previous version of python on your computer and the one you are trying to use

in that case : check the location of your working python:

which python And get sure it is matching the first line in your python code

#!<path_from_which_python_command>

Are there any disadvantages to always using nvarchar(MAX)?

Based on the link provided in the accepted answer it appears that:

100 characters stored in an nvarchar(MAX) field will be stored no different to 100 characters in an nvarchar(100) field - the data will be stored inline and you will not have the overhead of reading and writing data 'out of row'. So no worries there.
If the size is greater than 4000 the data would be stored 'out of row' automatically, which is what you would want. So no worries there either.

However...

You cannot create an index on an nvarchar(MAX) column. You can use full-text indexing, but you cannot create an index on the column to improve query performance. For me, this seals the deal...it is a definite disadvantage to always use nvarchar(MAX).

Conclusion:

If you want a kind of "universal string length" throughout your whole database, which can be indexed and which will not waste space and access time, then you could use nvarchar(4000).

Count cells that contain any text

Sample file

Note:

Tried to find the formula for counting non-blank cells (="" is a blank cell) without a need to use data twice. The solution for goolge-spreadhseet: =ARRAYFORMULA(SUM(IFERROR(IF(data="",0,1),1))). For excel ={SUM(IFERROR(IF(data="",0,1),1))} should work (press Ctrl+Shift+Enter in the formula).

Python TypeError: not enough arguments for format string

You need to put the format arguments into a tuple (add parentheses):

instr = "'%s', '%s', '%d', '%s', '%s', '%s', '%s'" % (softname, procversion, int(percent), exe, description, company, procurl)

What you currently have is equivalent to the following:

intstr = ("'%s', '%s', '%d', '%s', '%s', '%s', '%s'" % softname), procversion, int(percent), exe, description, company, procurl

Example:

>>> "%s %s" % 'hello', 'world'
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: not enough arguments for format string
>>> "%s %s" % ('hello', 'world')
'hello world'

how to create virtual host on XAMPP

Write these codes end of the C:\xampp\apache\conf\extra\httpd-vhosts.conf file,

DocumentRoot "D:/xampp/htdocs/foldername"
ServerName www.siteurl.com
ServerAlias www.siteurl.com
ErrorLog "logs/dummy-host.example.com-error.log"
CustomLog "logs/dummy-host.example.com-access.log" common

between the virtual host tag.

and edit the file System32/Drivers/etc/hosts use notepad as administrator

add bottom of the file

127.0.0.1    www.siteurl.com

How do I use this JavaScript variable in HTML?

<head>
    <title>Test</title>
</head>

<body>
    <h1>Hi there<span id="username"></span>!</h1>
    <script>
       let userName = prompt("What is your name?");
       document.getElementById('username').innerHTML = userName;
    </script>
</body>

MySQL DROP all tables, ignoring foreign keys

DB="your database name" \
    && mysql $DB < "SET FOREIGN_KEY_CHECKS=0" \
    && mysqldump --add-drop-table --no-data $DB | grep 'DROP TABLE' | grep -Ev "^$" | mysql $DB \
    && mysql $DB < "SET FOREIGN_KEY_CHECKS=1"

ASP.NET Web Api: The requested resource does not support http method 'GET'

If you are decorating your method with HttpGet, add the following using at the top of the controller:

using System.Web.Http;

If you are using System.Web.Mvc, then this problem can occur.

How to set a:link height/width with css?

Anchors will need to be a different display type than their default to take a height. display:inline-block; or display:block;.

Also check on line-height which might be interesting with this.

What is the difference between public, private, and protected?

When we follow object oriented php in our project , we should follow some rules to use access modifiers in php. Today we are going to learn clearly what is access modifier and how can we use it.PHP access modifiers are used to set access rights with PHP classes and their members that are the functions and variables defined within the class scope. In php there are three scopes for class members.

PUBLIC
PRIVATE
PROTECTED

Now, let us have a look at the following image to understand access modifier access level

Now, let us have a look at the following list to know about the possible PHP keywords used as access modifiers.

public :- class or its members defined with this access modifier will be publicly accessible from anywhere, even from outside the scope of the class.

private :- class members with this keyword will be accessed within the class itself. we can’t access private data from subclass. It protects members from outside class access.

protected :- same as private, except by allowing subclasses to access protected superclass members.

Now see the table to understand access modifier Read full article php access modifire

Print current call stack from a method in Python code

Install Inspect-it

pip3 install inspect-it --user

Code

import inspect;print(*['\n\x1b[0;36;1m| \x1b[0;32;1m{:25}\x1b[0;36;1m| \x1b[0;35;1m{}'.format(str(x.function), x.filename+'\x1b[0;31;1m:'+str(x.lineno)+'\x1b[0m') for x in inspect.stack()])

you can Make a snippet of this line

it will show you a list of the function call stack with a filename and line number

list from start to where you put this line

Scroll to bottom of div?

small addendum: scrolls only, if last line is already visible. if scrolled a tiny bit, leaves the content where it is (attention: not tested with different font sizes. this may need some adjustments inside ">= comparison"):

var objDiv = document.getElementById(id);
var doScroll=objDiv.scrollTop>=(objDiv.scrollHeight-objDiv.clientHeight);                   

// add new content to div
$('#' + id ).append("new line at end<br>"); // this is jquery!

// doScroll is true, if we the bottom line is already visible
if( doScroll) objDiv.scrollTop = objDiv.scrollHeight;

Excel VBA select range at last row and column

Another simple way:

ActiveSheet.Rows(ActiveSheet.UsedRange.Rows.Count+1).Select    
Selection.EntireRow.Delete

or simpler:

ActiveSheet.Rows(ActiveSheet.UsedRange.Rows.Count+1).EntireRow.Delete

How to retrieve Key Alias and Key Password for signed APK in android studio(migrated from Eclipse)

In any case you are confused with your password.You can use hit and trial. It will ask you for password.If it right then it will show you the list.

List item

$ keytool -list -v -keystore filename

Dump all tables in CSV format using 'mysqldump'

If you are using MySQL or MariaDB, the easiest and performant way dump CSV for single table is -

SELECT customer_id, firstname, surname INTO OUTFILE '/exportdata/customers.txt'
  FIELDS TERMINATED BY ',' OPTIONALLY ENCLOSED BY '"'
  LINES TERMINATED BY '\n'
  FROM customers;

Now you can use other techniques to repeat this command for multiple tables. See more details here:

Confirm password validation in Angular 6

I am using angular 6 and I have been searching on best way to match password and confirm password. This can also be used to match any two inputs in a form. I used Angular Directives. I have been wanting to use them

ng g d compare-validators --spec false and i will be added in your module. Below is the directive

import { Directive, Input } from '@angular/core';
import { Validator, NG_VALIDATORS, AbstractControl, ValidationErrors } from '@angular/forms';
import { Subscription } from 'rxjs';

@Directive({
  // tslint:disable-next-line:directive-selector
  selector: '[compare]',
  providers: [{ provide: NG_VALIDATORS, useExisting: CompareValidatorDirective, multi: true}]
})
export class CompareValidatorDirective implements Validator {
  // tslint:disable-next-line:no-input-rename
  @Input('compare') controlNameToCompare;

  validate(c: AbstractControl): ValidationErrors | null {
    if (c.value.length < 6 || c.value === null) {
      return null;
    }
    const controlToCompare = c.root.get(this.controlNameToCompare);

    if (controlToCompare) {
      const subscription: Subscription = controlToCompare.valueChanges.subscribe(() => {
        c.updateValueAndValidity();
        subscription.unsubscribe();
      });
    }

    return controlToCompare && controlToCompare.value !== c.value ? {'compare': true } : null;
  }

}

Now in your component

<div class="col-md-6">
              <div class="form-group">
                <label class="bmd-label-floating">Password</label>
                <input type="password" class="form-control" formControlName="usrpass" [ngClass]="{ 'is-invalid': submitAttempt && f.usrpass.errors }">
                <div *ngIf="submitAttempt && signupForm.controls['usrpass'].errors" class="invalid-feedback">
                  <div *ngIf="signupForm.controls['usrpass'].errors.required">Your password is required</div>
                  <div *ngIf="signupForm.controls['usrpass'].errors.minlength">Password must be at least 6 characters</div>
                </div>
              </div>
            </div>
            <div class="col-md-6">
              <div class="form-group">
                <label class="bmd-label-floating">Confirm Password</label>
                <input type="password" class="form-control" formControlName="confirmpass" compare = "usrpass"
                [ngClass]="{ 'is-invalid': submitAttempt && f.confirmpass.errors }">
                <div *ngIf="submitAttempt && signupForm.controls['confirmpass'].errors" class="invalid-feedback">
                  <div *ngIf="signupForm.controls['confirmpass'].errors.required">Your confirm password is required</div>
                  <div *ngIf="signupForm.controls['confirmpass'].errors.minlength">Password must be at least 6 characters</div>
                  <div *ngIf="signupForm.controls['confirmpass'].errors['compare']">Confirm password and Password dont match</div>
                </div>
              </div>
            </div>

I hope this one helps

Git mergetool generates unwanted .orig files

To be clear, the correct git command is:

git config --global mergetool.keepBackup false

Both of the other answers have typos in the command line that will cause it to fail or not work correctly.

Populating a razor dropdownlist from a List<object> in MVC

Your call to DropDownListFor needs a few more parameters to flesh it out. You need a SelectList as in the following SO question:

MVC3 DropDownListFor - a simple example?

With what you have there, you've only told it where to store the data, not where to load the list from.

How to return JSON data from spring Controller using @ResponseBody

I was using groovy+springboot and got this error.

Adding getter/setter is enough if we are using below dependency.

implementation 'org.springframework.boot:spring-boot-starter-web'

As Jackson core classes come with it.

PHP PDO: charset, set names?

You'll have it in your connection string like:

"mysql:host=$host;dbname=$db;charset=utf8"

HOWEVER, prior to PHP 5.3.6, the charset option was ignored. If you're running an older version of PHP, you must do it like this:

$dbh = new PDO("mysql:$connstr",  $user, $password);
$dbh->exec("set names utf8");

When to use NSInteger vs. int

You usually want to use NSInteger when you don't know what kind of processor architecture your code might run on, so you may for some reason want the largest possible integer type, which on 32 bit systems is just an int, while on a 64-bit system it's a long.

I'd stick with using NSInteger instead of int/long unless you specifically require them.

NSInteger/NSUInteger are defined as *dynamic typedef*s to one of these types, and they are defined like this:

#if __LP64__ || TARGET_OS_EMBEDDED || TARGET_OS_IPHONE || TARGET_OS_WIN32 || NS_BUILD_32_LIKE_64
typedef long NSInteger;
typedef unsigned long NSUInteger;
#else
typedef int NSInteger;
typedef unsigned int NSUInteger;
#endif

With regard to the correct format specifier you should use for each of these types, see the String Programming Guide's section on Platform Dependencies

How can I insert data into a MySQL database?

This way worked for me when adding random data to MySql table using a python script.
First install the following packages using the below commands

pip install mysql-connector-python<br>
pip install random

import mysql.connector
import random

from datetime import date


start_dt = date.today().replace(day=1, month=1).toordinal()
end_dt = date.today().toordinal()

mydb = mysql.connector.connect(
    host="localhost",
    user="root",
    password="root",
    database="your_db_name"
)

mycursor = mydb.cursor()

sql_insertion = "INSERT INTO customer (name,email,address,dateJoined) VALUES (%s, %s,%s, %s)"
#insert 10 records(rows)
for x in range(1,11):
    #generate a random date
    random_day = date.fromordinal(random.randint(start_dt, end_dt))
    value = ("customer" + str(x),"customer_email" + str(x),"customer_address" + str(x),random_day)
    mycursor.execute(sql_insertion , value)

mydb.commit()

print("customer records inserted!")

Following is a sample output of the insertion

cid       |  name      |  email           |    address        |  dateJoined  |

1         | customer1  |  customer_email1 | customer_address1 |  2020-11-15  |
2         | customer2  |  customer_email2 | customer_address2 |  2020-10-11  |
3         | customer3  |  customer_email3 | customer_address3 |  2020-11-17  |
4         | customer4  |  customer_email4 | customer_address4 |  2020-09-20  |
5         | customer5  |  customer_email5 | customer_address5 |  2020-02-18  |
6         | customer6  |  customer_email6 | customer_address6 |  2020-01-11  |
7         | customer7  |  customer_email7 | customer_address7 |  2020-05-30  |
8         | customer8  |  customer_email8 | customer_address8 |  2020-04-22  |
9         | customer9  |  customer_email9 | customer_address9 |  2020-01-05  |
10        | customer10 |  customer_email10| customer_address10|  2020-11-12  |

Getting a list of files in a directory with a glob

What about using NSString's hasSuffix and hasPrefix methods? Something like (if you're searching for "foo*.jpg"):

NSString *bundleRoot = [[NSBundle mainBundle] bundlePath];
NSArray *dirContents = [[NSFileManager defaultManager] directoryContentsAtPath:bundleRoot];
for (NSString *tString in dirContents) {
    if ([tString hasPrefix:@"foo"] && [tString hasSuffix:@".jpg"]) {

        // do stuff

    }
}

For simple, straightforward matches like that it would be simpler than using a regex library.

Regex find word in the string

How do I get indices of N maximum values in a NumPy array?

If you happen to be working with a multidimensional array then you'll need to flatten and unravel the indices:

def largest_indices(ary, n):
    """Returns the n largest indices from a numpy array."""
    flat = ary.flatten()
    indices = np.argpartition(flat, -n)[-n:]
    indices = indices[np.argsort(-flat[indices])]
    return np.unravel_index(indices, ary.shape)

For example:

>>> xs = np.sin(np.arange(9)).reshape((3, 3))
>>> xs
array([[ 0.        ,  0.84147098,  0.90929743],
       [ 0.14112001, -0.7568025 , -0.95892427],
       [-0.2794155 ,  0.6569866 ,  0.98935825]])
>>> largest_indices(xs, 3)
(array([2, 0, 0]), array([2, 2, 1]))
>>> xs[largest_indices(xs, 3)]
array([ 0.98935825,  0.90929743,  0.84147098])

How to use HTTP_X_FORWARDED_FOR properly?

I like Hrishikesh's answer, to which I only have this to add...because we saw a comma-delimited string coming across when multiple proxies along the way were used, we found it necessary to add an explode and grab the final value, like this:

$IParray=array_values(array_filter(explode(',',$_SERVER['HTTP_X_FORWARDED_FOR'])));
return end($IParray);

the array_filter is in there to remove empty entries.

Python: maximum recursion depth exceeded while calling a Python object

this turns the recursion in to a loop:

def checkNextID(ID):
    global numOfRuns, curRes, lastResult
    while ID < lastResult:
        try:
            numOfRuns += 1
            if numOfRuns % 10 == 0:
                time.sleep(3) # sleep every 10 iterations
            if isValid(ID + 8):
                parseHTML(curRes)
                ID = ID + 8
            elif isValid(ID + 18):
                parseHTML(curRes)
                ID = ID + 18
            elif isValid(ID + 7):
                parseHTML(curRes)
                ID = ID + 7
            elif isValid(ID + 17):
                parseHTML(curRes)
                ID = ID + 17
            elif isValid(ID+6):
                parseHTML(curRes)
                ID = ID + 6
            elif isValid(ID + 16):
                parseHTML(curRes)
                ID = ID + 16
            else:
                ID = ID + 1
        except Exception, e:
            print "somethin went wrong: " + str(e)

Is it possible to get the current spark context settings in PySpark?

If you want to see the configuration in data bricks use the below command

spark.sparkContext._conf.getAll()

What are MVP and MVC and what is the difference?

There are many answers to the question, but I felt there is a need for some really simple answer clearly comparing the two. Here's the discussion I made up when a user searches for a movie name in an MVP and MVC app:

User: Click click …

View: Who’s that? [MVP|MVC]

User: I just clicked on the search button …

View: Ok, hold on a sec … . [MVP|MVC]

( View calling the Presenter|Controller … ) [MVP|MVC]

View: Hey Presenter|Controller, a User has just clicked on the search button, what shall I do? [MVP|MVC]

Presenter|Controller: Hey View, is there any search term on that page? [MVP|MVC]

View: Yes,… here it is … “piano” [MVP|MVC]

Presenter: Thanks View,… meanwhile I’m looking up the search term on the Model, please show him/her a progress bar [MVP|MVC]

( Presenter|Controller is calling the Model … ) [MVP|MVC]

Presenter|Controller: Hey Model, Do you have any match for this search term?: “piano” [MVP|MVC]

Model: Hey Presenter|Controller, let me check … [MVP|MVC]

( Model is making a query to the movie database … ) [MVP|MVC]

( After a while ... )

-------------- This is where MVP and MVC start to diverge ---------------

Model: I found a list for you, Presenter, here it is in JSON “[{"name":"Piano Teacher","year":2001},{"name":"Piano","year":1993}]” [MVP]

Model: There is some result available, Controller. I have created a field variable in my instance and filled it with the result. It's name is "searchResultsList" [MVC]

(Presenter|Controller thanks Model and gets back to the View) [MVP|MVC]

Presenter: Thanks for waiting View, I found a list of matching results for you and arranged them in a presentable format: ["Piano Teacher 2001","Piano 1993"]. Please show it to the user in a vertical list. Also please hide the progress bar now [MVP]

Controller: Thanks for waiting View, I have asked Model about your search query. It says it has found a list of matching results and stored them in a variable named "searchResultsList" inside its instance. You can get it from there. Also please hide the progress bar now [MVC]

View: Thank you very much Presenter [MVP]

View: Thank you "Controller" [MVC] (Now the View is questioning itself: How should I present the results I get from the Model to the user? Should the production year of the movie come first or last...? Should it be in a vertical or horizontal list? ...)

In case you're interested, I have been writing a series of articles dealing with app architectural patterns (MVC, MVP, MVVP, clean architecture, ...) accompanied by a Github repo here. Even though the sample is written for android, the underlying principles can be applied to any medium.

Android XML Percent Symbol

to escape the percent symbol, you just need %%

for example :

String.format("%1$d%%", 10)

returns "10%"

ConfigurationManager.AppSettings - How to modify and save?

Perhaps you should look at adding a Settings File. (e.g. App.Settings) Creating this file will allow you to do the following:

string mysetting = App.Default.MySetting;
App.Default.MySetting = "my new setting";

This means you can edit and then change items, where the items are strongly typed, and best of all... you don't have to touch any xml before you deploy!

The result is a Application or User contextual setting.

Have a look in the "add new item" menu for the setting file.

How to convert a ruby hash object to JSON?

Add the following line on the top of your file

require 'json'

Then you can use:

car = {:make => "bmw", :year => "2003"}
car.to_json

Alternatively, you can use:

JSON.generate({:make => "bmw", :year => "2003"})

Programs & Examples On #Database relations

Difference between one-to-many and many-to-one relationship

How can I use querySelector on to pick an input element by name?

What does "request for member '*******' in something not a structure or union" mean?

Linq filter List<string> where it contains a string value from another List<string>

Include another HTML file in a HTML file

How to check the version of GitLab?

Creating a config file in PHP

Add data dynamically to an Array

How to display errors on laravel 4?

Python/Django: log to console under runserver, log to file under Apache

Android: How can I pass parameters to AsyncTask's onPreExecute()?

Add a common Legend for combined ggplots

How to initialize a private static const map in C++?

C# How to determine if a number is a multiple of another?

Simple WPF RadioButton Binding?

How to implement authenticated routes in React Router 4?

Download file of any type in Asp.Net MVC using FileResult?

Disabling Controls in Bootstrap

How to use XPath in Python?

What is the correct SQL type to store a .Net Timespan with values > 24:00:00?

How do I make an asynchronous GET request in PHP?

How to use parameters with HttpPost

How to view the list of compile errors in IntelliJ?

How to get element value in jQuery

How to set IntelliJ IDEA Project SDK

Moving uncommitted changes to a new branch

When should I use Lazy<T>?

How do I use a regex in a shell script?

How can I convert String to Int?

How to listen state changes in react.js?

Is it possible to set transparency in CSS3 box-shadow?

How do I link a JavaScript file to a HTML file?

Curl to return http status code along with the response

Add User to Role ASP.NET Identity

versionCode vs versionName in Android Manifest

Finding out the name of the original repository you cloned from in Git

Name attribute in @Entity and @Table

Get value from SimpleXMLElement Object

How to detect when keyboard is shown and hidden

callback to handle completion of pipe

How many socket connections can a web server handle?

How to determine the current iPhone/device model?

Launch iOS simulator from Xcode and getting a black screen, followed by Xcode hanging and unable to stop tasks

How can I include null values in a MIN or MAX?

Angular 2: How to call a function after get a response from subscribe http.post

How to put a div in center of browser using CSS?

'python3' is not recognized as an internal or external command, operable program or batch file

Python 3

Python2

How can I get table names from an MS Access Database?

Why does JSHint throw a warning if I am using const?

How to initialize/instantiate a custom UIView class with a XIB file in Swift

SQL Server: Difference between PARTITION BY and GROUP BY

MVC Razor @foreach

Add a new line to the end of a JtextArea

asp.net mvc3 return raw html to view

Regex to match URL end-of-line or "/" character

How to read data when some numbers contain commas as thousand separator?

What is the equivalent of Java's System.out.println() in Javascript?

Set a DateTime database field to "Now"

Difference between two dates in MySQL

Restart android machine

click or change event on radio using jquery

Convert a string to a double - is this possible?

How can I rename a single column in a table at select?

VS Code - Search for text in all files in a directory

JAXB: How to ignore namespace during unmarshalling XML document?

Handling ExecuteScalar() when no results are returned

Illegal string offset Warning PHP

TL;DR

In depth

Let's see that error:

What causes this?

What can be done?

Intellij Cannot resolve symbol on import

How to read a Parquet file into Pandas DataFrame?

what is the differences between sql server authentication and windows authentication..?

How do you print in a Go test using the "testing" package?

Generating a Random Number between 1 and 10 Java